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HUGHES— PRACTICE  OF  MEDICINE,  14th  RE- 
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It  is  a  reliable  guide  in  the  field  of  general  medicine,  giving 
practical  discussions  of  diseases,  synonyms,  definitions,  causes, 
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TRUMPER— MEMORANDA  OF   TOXICOLOGY 

2d  Edition.     Fabrikoid,   $1.50 

By  Max  Trumper,  Ph.  D.,  Formerly  Lecturer  on  Toxicology, 
Jefferson  Medical  College,  Philadelphia. 

The  author  has  had  much  hospital  experience  and  has  seen  cases 
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AUTENREITH— LABORATORY  MANUAL  FOR 
THE  DETECTION  OF  POISONS  AND  POWER- 
FUL DRUGS. 

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Completely  Revised  with  Extensive  Additions.  With  Colored 
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By  Dr.  Wilhelm  Autenreith,  Prof,  in  University  of  Freiburg;  Au- 
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Many  new  substances  and  methods  have  been  included  in  this 
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MORRIS— HUMAN  ANATOMY,  8th  EDITION 

1164  Illustrations,  515  in  Colors.    Cloth,  $10.00 

A  systematic  treatise  prepared  by  collaboration  of  a  number  of 
anatomists  and  Edited  by  C.  M.  Jackson,  M.S.,  M.D.,  Pro- 
fessor and  Director,  Department  of  Anatomy,  University  of 
Minnesota. 

ELLIS— ELEMENTS  OF  PATHOLOGY 

95  Illustrations.     Cloth,  $5.00 

By  Aller  G.  Ellis,  M.Sc..  M.D.  Rockefeller  Foundation 
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Department,  Chulalongkorn  University,  Bangkok,  Siam.  One- 
time Associated  Professor  of  Pathology,  Jefferson  Medical 
College,  Philadelphia. 

This  book  has  been  written  for  beginners  in  pathology.  A 
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I 

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fessor of  Obstetrics,  Jefferson  Medical  College  and  Hospital, 
Philadelphia. 

This  new  Edgar- Vaux  Obstetrics  is  a  distinctly  practical  guide, 
illustrated  in  detail  by  handsome  engravings.  The  descriptive 
text  is  concise.  It  has  been  the  aim  to  make  the  work  a  useful 
clinical  manual. 


? 


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OF 

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COMPENDS 


Each  Volume,  Cloth  $2.00. 

HUMAN  ANATOMY.  8th  Edition.  16  Plates,  139 
Text  Illustrations.  By  S.  O.  L.  Potter,  M.  D. 
Revised  by  D.  G.  Metheny,  M.  D. 

PHYSIOLOGY.     i6th    Edition.     27    Illustrations.     By 

A.  P.  Brubaker,  M.  D. 

OBSTETRICS.  loth  Edition.  80  Illustrations.  By 
H.  G.  Landis,  M.  D.  Revised  by  Dr.  Clifford 

B.  Lull,  M.  D. 

MATERIA  MEDICA,  THERAPEUTICS  AND  PRESCRIPTION 
WRITING.  9th  Edition.  Accord  with  U.  S. 
Phar.  X.  By  S.  O.  L.  Potter,  M.  D.  Revised 
by  A.  D.  Bush,  M.  D. 

GYNECOLOGY.  5th  Edition.  167  Illustrations.  By 
Wm.  H.  Wells,  M.  D.  Revised  by  W.  G.  Harer, 
M.  D. 

DISEASES  OF  THE  EYE  AND  REFRACTION.  4th  Edition. 
109  Illustrations.  By  G.  M.  Gould,  M.  D.  and 
W.  L.  Pyle,  M.  D. 

SURGERY.  Bandaging  and  Minor  Surgery.  185  Illus- 
trations. By  Benjamin  Lipshutz,  M.  D. 

MEDICAL  CHEMISTRY.  7th  Edition.  By  Henry  Leff- 
mann,  M.  D.  and  Max  Trumper,  A.  M. 

PHARMACY.  loth  Edition.  Based  upon  Remington's 
Pharmacy,  U.  S.  Phar.  and  U.  S.  Formulary.  By 
F.  E.  Stewart,  M.  D.  Revised  by  H.  W. 
Youngken,  M.  D. 

DISEASES  OF  THE  SKIN.  7th  Edition.  119  Illustra- 
tions. By  J.  F.  Schamberg,  M.  D. 

GENITO-URINARY  DISEASES  AND  SYPHILIS.  4th  Edi- 
tion. 44  Illustrations.  By  C.  S.  Hirsch,  M.  D. 

BACTERIOLOGY.  4th  Edition.  86  Illustrations.  By 
R.  L.  Pitfield,  M.  D. 

P.  BLAKISTON'S  SON  &  Co.  Philadelphia 


POTTER'S 

C  O  M  P  E  N  D 

OF 

HUMAN    ANATOMY 


REVISED  BY 

D.  GREGG  METHENY 

M.  D.,  L.  R.  C.  P.  AND   S.  (EDTN.),  L.  F.  P.  S.  (GLASGOW) 
ASSOCIATE  IN  ANATOMY,   JEFFERSON    MEDICAL  COLLEGE,   PHILADELPHIA 


EIGHTH  EDITION 

WITH  139  ILLUSTRATIONS;    ALSO  NUMEROUS  TABLES  AND 
16  PLATES  OF  THE  ARTERIES  AND  NERVES 


PHILADELPHIA 

P.  BLAKISTON'S  SON  &  CO.,  INC 

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COPYRIGHT,  1915,  BY  P.  BLAKISTON'S  SON  &  Co. 


PRINTED    IN    U.    S.    A. 
BY   THE   MAPLE    PRESS   COMPANY,    YORK,    PA. 


PREFACE  TO  THE  EIGHTH  EDITION 


After  many  years  of  wandering  in  the  embryological  minutiae  of  "  trans- 
cendental anatomy,"  it  has  at  last  become  apparent  to  most  teachers  and 
examiners  in  anatomy  that  the  only  kind  of  anatomy  that  could  be  of  any 
practical  value  to  a  physician  or  surgeon,  as  such,  is  the  anatomy  that 
can  be  actually  seen  and  handled.  Consequently  in  this  text,  details  of 
embryology,  histology,  and  physiology  have  been  largely  left  to  the  text- 
books dealing  with  those  subjects,  in  order  that  gross  human  anatomy 
might  be  the  more  thoroughly  explained. 

While  all  of  the  "recognized  authorities"  and  the  publications  of  the 
various  anatomical  associations  have  been  freely  consulted,  these  descrip- 
tions have  been  based  entirely  on  the  actual  facts  to  be  found  in  the  human 
body  and  are  not  dominated  by  any  one  single  authority.  The  many  new 
discoveries  and  the  changes  in  teaching  methods  that  have  been  made  in 
recent  years,  have  made  it  necessary  to  make  so  many  additions  and 
changes  in  the  text  that  the  entire  work  had  to  be  rewritten.  Parts  of 
the  nomenclature  of  the  German  Anatomical  Society  are  now  being  used 
so  universally,  that  it  became  necessary  to  include  it,  in  its  entirety,  in 
the  Latin  form.  However,  since  comparative  anatomy  has  been  almost 
entirely  ignored  in  the  B.N.A.,  and  as  so  many  of  its  terms  are  not  only 
inconsistent  but  also  evidence  personality  rather  than  broad  anatomical 
principles,  it  seems  certain  that  it  still  requires  much  revision  if  it  is  to 
endure;  therefore  while  the  B.N.A.  terms  are  given  in  the  Latin  form, 
only  such  of  them  as  seem  entitled  to  survival  are  given  in  the  English 
form  in  preference  to  the  older  regular  terms. 

It  is  confidently  hoped  that  the  student  will  find  these  descriptions 
not  only  accurate  and  up-to-date,  but  intelligible  as  well. 

D.  GREGG  METHENY. 

4609  SPRUCE  ST.,  PHILADELPHIA. 


•2.112.2, 


PREFACE  TO  THE  SEVENTH  EDITION 


The  twenty  years  which  have  elapsed  since  this  compend  was  first 
issued  have  brought  many  changes  of  nomenclature  and  description 
into  the  teaching  of  Anatomy.  The  present  edition  has  been  entirely 
re-written  and  brought  into  harmony  with  the  latest  text-books  on  this 
subject.  The  text  has  been  expanded  wherever  greater  detail  seemed 
desirable,  but  in  so  doing  the  condensed  form  of  statement  heretofore 
adopted  has  been  carefully  followed.  The  total  number  of  illustrations 
has  been  increased  from  117  to  138,  and  many  of  the  cuts  used  in  former 
editions  have  been  replaced  by  newer  ones.  The  Tables  and  Plates, 
heretofore  published  in  an  appendix,  have  been  thoroughly  revised, 
and  are  now  placed  in  their  natural  positions  in  the  text.  These  changes 
have  increased  the  size  of  the  volume  by  82  pages,  and  have  made  it 
practically  a  new  book,  which  the  author  hopes  will  receive  a  continu- 
ance of  the  favor  heretofore  extended  to  the  previous  editions. 

Originally  designed  for  the  use  of  the  medical  student  in  preparing 
for  the  exercises  of  the  quiz-room  and  for  his  examinations,  the  text  is 
confined  to  the  essentials  of  each  structure  treated  of,  which  are  arranged 
in  such  a  manner  as  to  facilitate  their  rapid  acquirement.  All  super- 
fluities of  description  have  been  studiously  avoided,  and  only  such  matter 
inserted  as  should  be  thoroughly  known  in  order  to  pass  a  rigid  examina- 
tion on  any  organ  or  structure  of  the  human  body.  The  descriptions  will 
be  found  to  closely  follow  Gray,  though  Morris,  Quain,  and  other  recog- 
nized authorities  have  been  freely  consulted  during  the  preparation  of 
the  text.  For  many  of  the  special  arrangements  the  author  is  indebted 
to  the  lectures  of  Professor  W.  H.  Pancoast,  formerly  of  Jefferson  Medical 

vii 


Vlll  PREFACE    TO    THE    SEVENTH    EDITION 

College,  and  to  the  quizzes  of  Dr.  Henry  Morris,  at  one  time  assistant 
to  the  chair  of  Anatomy  in  the  same  school. 

While  striving  to  carry  out  the  object  of  this  series  in  furnishing  the 
medical  student  with  a  condensed  manual  of  Anatomy,  the  author  has 
endeavored,  from  a  strong  appreciation  of  the  importance  of  the  subject, 
to  make  this  volume  deserving  of  first  rank  among  its  kind;  and  believing 
that  a  judicious  condensation,  which  does  not  slight  the  essential  features 
of  the  subjects  treated,  cannot  fail  to  be  of  benefit  in  any  department 
of  science,  he  again  commits  this  compend  to  the  teachers  and  students 
of  Anatomy,  in  the  hope  that  it  may  continue  to  be  found  worthy  of  a 
place  alongside  the  more  exhaustive  and  exhausting  text-books. 

SAM'L  O.  L.  POTTER. 


CONTENTS 


FACE 

OSTEOLOGY i 

BONES  OF  THE  TRUNK.   .    .    . 5 

VERTEBRAL  COLUMN 5 

THORAX 7 

PELVIS 9 

BONES  OF  THE  HEAD 14 

ORBITS 35 

FOSSAE 37 

SUTURES  AND  FONTANELLES 39 

FORAMINA  AT  THE  BASE  OF  THE  SKULL 41 

POINTS  AT  THE  BASE  OF  THE  SKULL 44 

BONES  OF  THE  UPPER  EXTREMITY 44 

OF  THE  SHOULDER 44 

OF  THE  ARM 47 

OF  THE  FOREARM 48 

OF  THE  HAND 50 

BONES  OF  THE  LOWER  EXTREMITY 52 

OF  THE  THIGH 52 

OF  THE  LEG 54 

OF  THE  FOOT 56 

ARTICULATIONS 58 

ARTICULATIONS  OF  THE  TRUNK 60 

OF  THE  UPPER  EXTREMITY .* 64 

OF  THE  LOWER  EXTREMITY 68 

MUSCLES  AND  FASCIAE 73 

MUSCLES  OF  THE  HEAD 75 

OF  THE  EAR 79 

OF  THE  NECK 80 

ix 


X  CONTENTS 

PAGE 

OF  THE  LARYNX  AND  EPIGLOTTIS 85 

OF  THE  BACK 86 

OF  THE  THORAX 93 

OF  THE  ABDOMEN 95 

OF  THE  PELVIC  OUTLET 97 

OF  THE  PERINEUM 98 

OF  THE  UPPER  EXTREMITY 99 

OF  THE  LOWER  EXTREMITY 107 

FASCIA  OF  THE  HAND 105 

LUMBO-DORSAL 90 

OF  THE  ILIAC  REGION 107 

OF  THE  THIGH 108 

OF  THE  FOOT 115 

THE  BLOOD-VASCULAR  SYSTEM 118 

HEART 118 

ARTERIES      122 

PULMONARY  ARTERY  AND  AORTA 122 

ARTERIES  OF  THE  HEAD  AND  NECK 124 

CIRCLE  OF  WILLIS 128 

TRIANGLES  OF  THE  NECK 128 

ARTERIES  OF  THE  UPPER  EXTREMITY 130 

OF  THE  TRUNK 136 

OF  THE  LOWER  EXTREMITY 141 

ARTERIAL  ANASTOMOSES 145 

TABLES  AND  PLATES  OF  THE  ARTERIAL  SYSTEM    .  147 

VEINS  OF  THE  HEAD  AND  NECK 163 

OF  THE  UPPER  EXTREMITY 166 

OF  THE  THORAX 167 

OF  THE  LOWER  EXTREMITY,  PELVIS  AND  ABDOMEN.    .    .    .  168 

OF  THE  HEART 171 

THE  LYMPHATIC  SYSTEM 171 

LYMPHATICS  OF  THE  HEAD  AND  NECK 172 

OF  THE  UPPER  AND  LOWER  EXTREMITIES 173 

OF  THE  PELVIS,  ABDOMEN,  INTESTINES,  THORAX    .    .    .    .174 


CONTENTS  XI 

PAGE 

THE  NERVOUS  SYSTEM 175 

BRAIN 178 

MENINGES 180 

CEREBRUM 183 

CEREBELLUM 206 

MEDULLA  OBLONGATA 208 

NERVE-TRACTS  IN  THE  BRAIN 212 

SPINAL  CORD  213 

NERVE-TRACTS  IN  THE  SPINAL  CORD 214 

CRANIAL  NERVES 216 

GANGLIA  OF  THE  CRANIAL  NERVES 223 

SPINAL  NERVES .' 226 

CERVICAL  NERVES 227 

THORACIC  NERVES ' 231 

LUMBAR  NERVES 232 

SACRAL  AND  COCCYGEAL  NERVES 233 

SYMPATHETIC  SYSTEM 236 

GANGLIATED  CORD 237 

GREAT  PLEXUSES 239 

TABLES  AND  PLATES  OF  THE  NERVOUS  SYSTEM.    .   243 

ORGANS  OF  SPECIAL  SENSE 270 

SKIN 270 

APPENDAGES  OF  THE  SKIN    . 272 

TONGUE 273 

NOSE 276 

EYE 280 

SCLEROTIC  AND  CORNEA 281 

CHOROID,  CILIARY  BODY  AND  IRIS 283 

RETINA 285 

MUSCLES  AND  NERVES  OF  THE  EYEBALL 289 

VESSELS  AND  NERVES  OF  THE  EYE 289 

APPENDAGES  OF  THE  EYE 293 

EAR 296 

EXTERNAL  EAR 297 

MEMBRANA  TYMPANI      298 


Xll  CONTENTS 

PAGE 

TYMPANUM 300 

EUSTACHIAN  TUBE 303 

INTERNAL  EAR 304 

AUDITORY  NERVE 310 

ORGANS  OF  DIGESTION 312 

MOUTH •    •  312 

PALATE  AND  TONSILS 313 

SALIVARY  GLANDS 315 

TEETH 317 

PHARYNX      .    .    '. 320 

(ESOPHAGUS - 322 

ABDOMEN 323 

PERITONEUM 325 

STOMACH 328 

SMALL  INTESTINE 33o 

LARGE  INTESTINE 333 

LIVER 336 

STRUCTURE    .    .    .' 339 

VESSELS 341 

EXCRETORY  APPARATUS. 342 

PANCREAS 343 

LESSER  PANCREAS 344 

DUCTLESS  GLANDS 344 

THYROID  AND   THYMUS   GLANDS 345 

SPLEEN 348 

ORGANS   OF  VOICE  AND  RESPIRATION 350 

LARYNX 350 

TRACHEA  AND  BRONCHI 355 

PLEURAE 356 

MEDIASTINUM 356 

LUNGS 357 

THE  URINARY  ORGANS  .  .  360 


CONTENTS  Xlll 

PACE 

KIDNEYS 360 

URETERS 363 

SUPRA-RENAL  CAPSULES 364 

BLADDER 365 

MALE  URETHRA 368 

FEMALE  URETHRA 37° 

THE  MALE  ORGANS  OF  GENERATION 370 

URETHRAL  GLANDS  IN   THE   MALE 370 

PENIS 37i 

TESTES 372 

APPENDAGES  OF  THE  TESTES 375 

THE  FEMALE  ORGANS  OF  GENERATION 377 

VULVA 377 

VAGINA 379 

UTERUS 380 

APPENDAGES  OF  THE  UTERUS 382 

MAMM.E 383 

HSRNIA 384 

INGUINAL  HERNIA 385 

FEMORAL  HERNIA 388 

THE  PERINJEUM 39* 

PELVIC  CAVITY  AND  FASCIA 391 

MALE  PERINEUM 393 

ISCHIO-RECTAL   REGION 394 

FEMALE  PERINEUM 395 

LITHOTOMY 396 

INDEX  .  399 


XIV 


ABBREVIATIONS — EXPLANATION 


ABBREVIATIONS 


Anas.  .  . 
Ant.  .  . 
Art.  or  A. 
Asc.  .  . 
Br.  .  .  . 
Cerv.  .  . 
Com.  .  . 
Commun. 
Desc.  .  . 
Ext. 


Anastomoses. 

Inf.    .    .    . 

Inferior. 

Anterior. 

Int.   .    .    . 

Internal. 

Artery. 

L  

Left. 

Ascending. 

M  

Middle. 

Branch. 

N  

Nerve. 

Cervical. 

PI  

Plexus. 

Common. 

Post..    .    . 

Posterior. 

Communicating. 

R  

Right. 

Descending. 

Sup.  .    .    . 

Superior. 

External. 

Superf  .  .    . 

Superficial. 

Trans  . 

.   Transverse. 

EXPLANATION 


Figures  or  letters  in  parentheses,  .thus — (14),  (a),  refer  to  the  same 
figures  or  letters  on  the  adjoining  illustration;  except  in  the  Tables  of 
Arteries,  in  which  figures  in  parentheses  serve  as  cross-references  to  other 
divisions  of  the  tables. 


A  COMPEND  OF 

HUMAN  ANATOMY 


The  term  Anatomy  is  derived  from  the  Greek  a.va,  through,  and 
T\nv€i,v,  to  cut,  it  strictly  means  dissection,  but  is  technically  applied  to 
that  science  which  treats  of  the  structure  of  organized  bodies. 

The  divisions  of  Descriptive  Human  Anatomy  are, — Osteology,  the 
anatomy  of  the  bones;  Syndesmology,  of  the  joints;  Myology,  of  the  muscles; 
Angiology,  of  the  vessels;  Neurology,  of  the  nerves;  Splanchnology,  of  the 
internal  viscera;  Adenology,  of  the  glands;  Dermatology,  of  the  skin; 
Genesiology,  of  the  generative  organs. 

OSTEOLOGY 

The  number  of  Bones  in  the  Adult  Human  Skeleton  is  variously 
stated  by  different  anatomists.  Excluding  the  teeth  (which  belong  to 
the  tegumentary  system),  the  Wormian  and  the  sesamoid  bones,  the 
number  is  206.  Excluding  also  the  6  ossicles  of  the  middle  ear  the  whole 
number  would  be  200.  Leaving  out  also  the  2  patellae  and  the  hyoid 
bone,  the  number  in  the  skeleton  proper  would  be  197  bones.  Of  these, 
the  vertebral  column  contains  26,  the  cranium  8,  the  face  14,  the  walls  of 
the  thorax  (sternum  and  ribs)  25,  the  upper  extremities  64,  and  the  lower 
extremities  60.  They  are  divisible  into  four  classes, — the  long  and  short 
medullated,  and  the  flat  and  irregular  cancellous  bones. 

Long  Bones  number  90,  act  as  supports,  or  levers,  and  are  known  by 
having  a  medullary  canal. in  the  centre  of  each,  a  shaft  (diaphysis),  and 
two  extremities.  They  are  developed  by  osseous  deposit  in  cartilage,  and 
include  the  clavicle,  humerus,  radius,  ulna,  femur,  tibia,  fibula,  meta- 
carpal  and  metatarsal  bones,  and  the  phalanges. 

Short  Bones  number  30,  and  are  found  where  strength  is  required,  but 
limited  motion.  They  are  also  developed  by  osseous  deposit  in  cartilage 
and  include  the  bones  of  the  carpus  and  tarsus,  the  former  having  16  and 
the  latter  14. 


2  HUMAN    ANATOMY 

Flat  Bones  number  38,  protect  the  viscera  by  forming  walls  around  them, 
and  afford  extensive  attachment  for  muscles.  They  are  developed  by 
osseous  deposit  in  membranes,  and  consist  of  2  dense  layers,  separated  by 
a  cellular  or  cancellous  osseous  tissue,  the  diploe.  They  include  the  oc- 
cipital (os  occipitale),  parietal  (os  parietale),  and  frontal  (os  frontale) 
'(bones  of  the  cranium);  the  nasal  (os  nasale),  lacrimal  (os  lacrimale), 
and  vomer  (bones  of  the  face);  the  scapula,  os  innominatum  (os  coxae), 
sternum  and  ribs  (costae). 

Irregular  Bones  are  39  in  number,  and  include  the  vertebrae,  sacrum, 
coccyx  (coccygis),  the  temporal,  ethmoid,  and  sphenoid  bones,  and 
the  bones  of  the  face,  except  the  nasal  (os  nasale),  lacrimal  (os  lacrimale), 
and  vomer. 

Bones  of  the  Head  number  22,  and  comprise  the — 
Cranial  Bones  8, — the  frontal,  2  parietal  (ossa  parietalia) ,  occipital  (os 

occipitale),  2  temporal  (ossa  temporalia),  the  sphenoid  and  the  ethmoid 

(os  ethmoidale) . 
Facial  Bones  14, — 2  maxillary  (maxillae),  2  malar  (ossa  zygomatica),  2 

nasal   (ossa  nasalia),    2    lacrrmal    (ossa    lacrimalia),    2  palate   (ossa 

palatina),  2  inferior  turbinal  (conchae  nasales  inferiores),  vomer  and 

mandible. 

Bones  of  the  Trunk  number  53,  as  follows,  viz. — 
Vertebra  24, — 7  cervical,  12  thoracic,  and  5  lumbar  vertebrae. 
Thorax  25, — 7  pairs  of  true  ribs,  3  pairs  of  false  ribs,  2  pairs  of  floating 

ribs  (articulating  with  the  bodies  of  the  thoracic  vertebrae),  and  the 

sternum. 
Pelvis  4, — the  sacrum,  the  coccyx  (os  coccygis),  and  2  ossainnominata  (ossa 

coxae)    each  os   innominatum    consisting   of   3, — the    ilium    (coxae), 

ischium,   and  pubis. 

Bones  of  each  Upper  Extremity  number  32,  as  follows: — 
Shoulder  2, — the  clavicle  (clavicula)  and  scapula. 
Arm  i, — the  humerus. 
Forearm  2, — the  radius  and  ulna. 
Hand  27, — 8  carpal  bones, — the  scaphoid  (os  naviculare),  semilunar  (os 

triquetrum),  cuneiform,  pisiform  (os  pisiforme),  trapezium  (os  mul- 

tangulum  majus),   trapezoid    (os   multangulum   minus),   os   magnum 

(os  capitatum),  and  unciform  (os  hamatum), — 5  metacarpal,  and  14 

phalanges. 

Bones  of  each  Lower  Extremity  number  29,  viz. — 
Thigh  i, — the  femur. 
Leg  2, — the  tibia  and  fibula. 


OSTEOLOGY  3 

Foot  26, — 7  tarsal  bones, — the  astragalus  (talus),  os  calcis  (calcaneus), 

scaphoid,  (naviculare  pedis),  cuboid  (os  cuboideum),  external,  (tertium) 

middle  (secundum),  and  internal  cuneiform  (primum), — 5  meta tarsal, 

14  phalanges. 

Unclassified  Bones  are  the— 
Patella  2,  which  are  sesamoid  bones,  each  developed  in  the  tendon  of  the 

quadriceps  extensor  femoris  muscle. 
Hyoid  Bone  (os  hyoideum)  i, — the  tongue-bone  not  articulated  to  the 

skeleton. 
Malleus,  Incus  Stapes  (3  pairs), — the  bones  of  the  middle  ear    (ossicula 

auditis). 
Sesamoid  Bones,  of  variable  number,  situated  in  the  tendons  of  the 

gastrocnemius  and  peroneus  longus  muscles,  and  in  the  flexor  tendons 

of  the  great  toe  and  the  thumb. 
Wormian   Bones    (ossa    Suturarum),    sometimes    found   in    the   cranial 

sutures,  are  not  constant  in  number  or  size. 

Principal  Eminences  on  Bones.  Heads  are  convex  and  smooth,  for 
articulation  in  movable  joints.  Condyles  are  irregularly  shaped  heads. 
Trochamers,  when  for  turning  the  bone.  Tuberosities  are  broad,  uneven 
prominences.  Tubercles  are  small  tuberosities.  Spines,  or  Spinous  proc- 
esses, when  sharp  and  slender.  Apophysis  (an  excrescence),  is  a  process 
or  marked  bony  prominence  which  has  never  been  separate  from  the 
bone.  Epiphysis  (an  accretion),  is  a  process  which  was  developed  sepa- 
rately and  afterward  became  united  to  the  bone  by  ossification  of  the 
intermediate  tissue. 

Other  Names  given  to  Bony  Prominences.  There  are  several  adject 
tives  applied  to  them  from  their  fancied  resemblances,  such  as — Azygod, 
without  a  fellow;  Clinoid,  like  a  bed;  Coracoid,  like  a  crow's  beak;  Coronoi,- 
hooked  like  a  cow's  horn;  Hamular,  hook-like;  Malleolar,  like  a  mallet; 
Mastoid,  like  a  nipple;  Odontoid,  tooth-like;  Pterygoid,  wing-like;  Rostrum, 
a  beak;  Spinous,  thorn-like;  Styloid,  pen-like;  Squamous,  scaly;  Vaginal, 
ensheathing,  etc. 

Cavities  of  Bones.  Articular  cavities  are  called  Cotyloid,  cup-like; 
Ctenoid,  shallow;  Trochlear,  pulley-like;  Facet,  if  smooth;  Alveolar  or 
Alveoli,  when  socket-like.  Non-articular  cavities  are  named  fossae,  sinu- 
ses, aqueducts,  foramina,  canals,  fissures,  notches,  cells,  grooves,  depres- 
sions, etc. 

Composition  of  Bone.  Organic  or  animal  matter,  about  ^,  consisting 
of  gelatin,  vessels  and  fat.  Inorganic,  or  mineral,  about  %,  consisting  of 


4  HUMAN   ANATOMY 

phosphate  and  carbonate  of  calcium  (62^  per  cent.),  with  fluoride  of 
calcium,  phosphates  of  magnesium,  sodium,  and  chloride  of  sodium  (4^ 
per  cent.).  Heat  will  remove  the  organic  matter  and  leave  the  inorganic; 
dilute  Nitric  or  Hydrochloric  acid  will  remove  the  inorganic,  and  leave  the 
organic.  In  old  age  the  inorganic  constituents  predominate,  and  the  bones 
are  brittle;  in  youth  the  organic  predominate,  and  epiphyseal  dislocation 
is  more  common  than  fracture,  especially  in  the  long  bones  of  the 
extremities. 

Structure  of  Bone.  Bone  is  composed  of  an  outer  compact  layer,  and 
an  inner  cellular  or  spongy  structure.  It  is  surrounded,  except  at  the  articu- 
lar cartilages,  by  a  vascular  fibrous  membrane,  the  Periosteum,  which 
receives  the  insertions  of  all  tendons,  ligaments,  etc.;  and  the  central  cavity 
of  long  bones  is  lined  by  a  similar  structure,  the  Endosteum.  The  trans- 
verse section  of  the  bone,  examined  microscopically,  shows — 

Haversian  Canals, — diameter  /^oo  inch,  for  the  passage  of  vessels. 

Canaliculi, — diameter  Keooo  inch,  radiating  from  the  canals,  and  con- 
necting them  with  the  lacunae. 

Lacuna, — arranged  circularly  around  the  canals,  and  contain  the 
bone-cells,  appearing  as  irregular  dark  spaces. 

Haversian  Spaces, — connect  the  canals  with  the  medullary  spaces,  and 
divide  one  Haversian  system  from  another.  An  Haversian  System 
comprises  an  Haversian  canal  with  its  lamellae,  lacunae,  and  canaliculi. 

Concentric  Lamella, — of  bone  tissue,  around  the  canals. 

Circumferential  Lamella, — are  bone  layers  binding  the  canals  together. 
~j  Interstitial  Lamella, — woven  in  between  the  concentric  lamellae. 

The  Marrow  of  Bone.  In  young  bones  it  is  a  tenacious,  transparent 
fluid,  free  from  fat.  In  adult  bones  it  is  of  a  yellow  color,  and  consists 
of  fat  in  varying  proportion  and  extractive  matters.  It  is  found  in  the 
medullary  canal,  the  cancellous  texture,  and  the  large  Haversian  spaces. 

Vessels  found  in  Bones.  Arteries,  veins,  and  some  say  lymphatics. 
The  Arteries  are, — the  nutrient,  entering  at  the  nutrient  foramen;  the 
articular,  nourishing  the  cancellous  structure;  and  the  periosteal,  which 
supply  the  periosteum  and  the  compact  structure.  The  Veins  emerge 
from  the  ends,  the  shaft,  and  from  the  nutrient  foramen. 

The  process  of  Ossification.  The  site  of  bone  is  first  occupied  by  a 
mucoid  substance,  which  becomes  temporary  cartilage  (blastema)  in  the 
second  month  of  foetal  life.  The  young  bone-cells  (osteo-blasts)  are 
then  deposited  in  the  cartilage  at  certain  points,  and  their  deposition 
and  subsequent  pressure  cause  the  absorption  of  the  cartilage.  In  most  of 
the  bones  of  the  head  and  face,  ossification  is  intra-membranous  instead 


THE   VERTEBRAL   COLUMN  5 

of  intra-cartilaginous.  The  first  bones  in  which  ossification  appears  are 
the  clavicle  and  inferior  maxillary  (5th  to  7th  foetal  week);  the  last  is  the 
pisiform  bone  (i2th  year).  Epiphyses  ossify  after  birth  and  begin  uniting 
to  the  bone  from  the  age  of  puberty,  and  in  the  inverse  order  to  that  in 
which  their  ossification  began,  except  the  lower  end  of  the  fibula,  which 
ossifies  and  is  joined  to  the  shaft  earlier  than  its  upper  end. 

,    THE  BONES  OF  THE  TRUNK 

A*-3V 

THE  VERTEBRAL  COLUMN 

Characteristics  common  to  the  Vertebrae.  Each  of  the  24  spinal 
vertebrae  consists  of  a  body  and  an  arch,  the  latter  being  formed  by  2 
radix  arcus  vertebrae  (pedicles)  and  2  laminae,  which  support  7  processes. 
The— 

Body  (corpus  vertebrae)  is  thick  and  spongy,  convex  in  front  (i)  from  side 

to  side,  concave  vertically,  and  on  the  upper  and  lower  surfaces,  which 

are  surrounded  by  a  bony  rim.  PIG.  i. 

Anteriorly   are   small   foramina 

for  nutrient  vessels,  posteriorly 

a  large  foramen  for  the  exit  of  5! 

the  venae  basis  vertebrarum. 
Pedicles  (radix  arcus  vertebrae)  (7), 

— project    backward    from   the 

body,   inclining    outwardly. 

They   are   notched    above   and 

below  (incisura  vertebralis  su- 
perior et  inferior),  thus  form- 
ing, with  the  adjacent  notches, 

the      Inter  vertebral     Foramina 

(Foramina  Intervertebralia)  for  the  entrance  of  vessels  and  the  exit 

of  the  spinal  nerves. 
Lamina, — are  2  broad  plates,  meeting  in  the  spinous  process  behind, 

and  rough  on  their  upper  and  lower  borders  for  the  attachment  of 

the  ligamentum  subflava. 
Transverse  Processes  (4), — one  on  each  side  projecting  outward;  those 

of  the  first  ten  thoracic  vertebrae  have  articular  facets  (5)  for  the 

tubercles  of  the  ribs. 
Articular  Processes  (Zygapophyses)   (6), — two  on   each  side,  superior 

(6)  and  inferior,  project  from  the  junction  of  the  laminae  and  pedicles, 

and  articulate  above  and  below  with  the  articular  processes  of  the 


HUMAN   ANATOMY 


adjacent  vertebrae.  Their  upper  facets  look  backwards  and  upwards 
in  the  cervical  region,  backwards  and  outwards  in  the  thoracic,  and 
backwards  and  inwards  in  the  lumbar. 

Spinous  Process  (3), — projects  backward  from  the  junction  of  the  laminae 
with  each  other,  sometimes  very  obliquely. 

Spinal  Foramen  (foramen  vertebrale)  (2),— is  the  space  enclosed  by  the 
body,  pedicles  and  laminae,  and  which,  when  the  vertebrae  are  articu- 
lated, forms  part  of  the  spinal  or  neural  canal. 

The  Spinal  Vertebrae  are  distinguished  as  cervical  7,  thoracic  12, 
and  lumbar  5.  Each  of  these  divisions  has  several  peculiar  features,  but 
their  especial  characteristics  are  as  follows: — 

Cervical  Vertebra, — are  pierced  at  the  bases  of  their  transverse  processes 
by  the  costo-transverse  foramina,  which  transmit  the  vertebral  artery, 
vein,  and  plexus.  The  anterior  boundary  of  a  costo-transverse 
foramen  is  called  the  Costal  process,  it  is  a  true  cervical  rib.  Its 
termination  is  called  anterior  tubercle  of  the  transverse  process.  The 
posterior  tubercle  is  the  tip  of  the  true  transverse  process.  The 
superior  articular  facets  look  backwards  and  upwards. 

Thoracic  Vertebrae, — have  facets  and  demifacets  on  their  bodies,  for 
articulation  with  the  heads  of  the  ribs,  these  facets  are  called  the 
foveae  costales.  The  superior  articular  facets  look  backwards  and 
outwards. 

Lumbar  Vertebra, — are  marked  by  the  absence  of  the  foramina  and  facets 
which  distinguish  the  other  two  classes.  The  superior  articular  facets 
look  backwards  and  inwards. 

Peculiar  Vertebrae  are  9  in  number, — the  Atlas  or  ist  cervical,  the  Axis 
or  2d  cervical  (epistropheus),  the  Vertebra  Prominens,  or  7th  cervical 

(the  ist  thoracic  is  nearly  always 
more    prominent),  the   ist,  Qth, 
icth,    nth,    and    i2th  thoracic, 
and  the  5th  lumbar.     The — 
^Jlas  (3), — is  a  bony  ring  sup- 
porting the  head.     A  bony 
arch   takes  the   place  of  a 
body,  and  its  spinous  process 
is  a  mere  tubercle.     Its  Lat- 
eral   Masses    (i)     form    its 

chief  bulk,  supporting  large  Articular  Processes  (foveae  articulares), 
which  look  inwards,  the  superior  (2)  articulating  with  the  condyles 
of  the  occipital  bone. 


FIG.  2. 


THE    THORAX  7 

Axis  (9), — is  marked  by  its  Odontoid  Process  (dens)  (10)  projecting  up- 
ward from  the  body  into  the  anterior  part  of  the  spinal  foramen  of 
the  atlas,  where  it  articulates  with  the  anterior  arch  (3),  and  receives 
the  occipito-axoid  (ligamentum  apicis  dentis)  and  the  check  liga- 
ments (ligamenta  alaria).  Its  transverse  processes  (8)  are  very  small 
and  are  not  bifid.  Its  inferior  articular  surfaces  (7)  have  the  same 
direction  as  those  of  the  other  cervical  vertebrae. 

Vertebra  Prominens, — has  a  long  and  prominent  spinous  process  which 
ends  in  a  tubercle  for  the  ligamentum  nuchae. 

Thoracic  Vertebra.  The  ist  has  one  facet  and  a  demifacet  for  the  ist 
and  2d  ribs.  The  gth  has  a  demifacet  only.  The  loth  has  but  one 
facet  on  the  body  and  one  on  the  transverse  process.  The  nth  and 
1 2th  have  each  but  one  facet  on  the  body,  and  none  on  the  transverse 
processes.  The  i2th  resembles  a  lumbar  vertebra  in  size  and  shape. 

5th  Lumbar  Vertebra, — is  much  deeper  in  front  than  behind;  its  spinous 
process  is  small,  but  its  transverse  processes  are  large  and  thick,  and 
point  slightly  upward. 

Important  Relations  of  Certain  Vertebrae. 

3<f  Cervical  corresponds  in  situation  to — the  bifurcation  of  the  common 
carotid  artery,  and  the  superior  cervical  ganglion. 

5fh  Cervical,  to — the  junctions  of  the  larynx  with  the  trachea  and  the 
pharynx  with  the  oesophagus,  and  the  middle  cervical  ganglion  of  the 
sympathetic. 

id  Lumbar,  to — the  junction  of  the  duodenum  with  the  jejunum,  the  com- 
mencement of  the  thoracic  duct  and  the  portal  vein,  the  origin  of  the 
superior  mesenteric  artery,  the  lower  margin  of  the  pancreas,  the  opening 
of  the  ductus  communis  choledochus,  the  lower  end  of  the  spinal  cord, 
and  the  crura  of  the  diaphragm. 

[The  sacral  and  coccygeal  vertebrae  are  described  as  bones  of  the  pelvis.] 

THE  THORAX 

The  Thorax  is  an  osseo-cartilaginous  cage  formed  by  the  bodies  of  the 
dorsal  vertebrae  posteriorly,  the  ribs  and  costal  cartilages  laterally,  and 
the  sternum  in  front.  Its  shape  is  conical,  the  axis  inclined  forward,  the 
base  below  and  closed  by  the  diaphragm. 

Structures  passing  through  its  Apex,  are — the  trachea,  oesophagus, 
large  vessels  of  the  neck,  pneumogastric  (vagus),  phrenic,  and  sympathetic 
nerves,  thoracic  duct,  and  in  inspiration  the  apex  of  the  lung. 


8 


HUMAN   ANATOMY 


FIG.  3. 


Structures  contained  in  its  Cavity,  are — the  trachea,  bronchi  and 
lungs,  the  heart  and  great  vessels,  internal  mammary  arteries,  azygos  and 
bronchial  veins,  pneumogastric,  phrenic,  and  splanchnic  nerves,  oesopha- 
gus, thoracic  duct,  lymphatic  vessels  and  glands. 

The  Sternum,  or  breast-bone,  consists  of  3  parts — the  manubrium  (i), 
or  handle;  the  gladiolus  (2),  or  sword;  and  the  ensiform  or  xiphoid  appen- 
dix (3).  It  presents  the — 

Inter  clavicular  Notch, — on  its  superior  border. 

Manubrium  (i), — articulates 
with  the  clavicle,  ist  costal 
cartilage,  and  a  part  of 
the  2d. 

Gladiolus  (2), — articulates 
with  the  costal  cartilages 
from  the  3d  to  the  6th  in- 
clusive, and  partly  with 
the  2d  and  7th. 
Ensiform  Appendix  (3), — ar- 
ticulates with  the  cartilage 
of  the  false  ribs,  and  in 
part  with  the  7th  costal 
cartilage.  It  is  cartilag- 
inous in  youth. 
Development  and  Muscles. 
The  sternum  is  developed-  by  6 
centres,  i  each  for  the  manu- 
brium and  ensiform  appendix 
and  4  for  the  gladiolus.  The 
muscles  attached  to  it  are  9  pairs  and  one  single  muscle, — the  sterno- 
cleido-mastoid,  sterno-hyoid  and  sterno-thyroid,  3,  to  its  upper  part; — 
the  rectus  abdominis,  external  and  internal  oblique,  transversalis  and  the 
diaphragm,  5,  to  its  lower  part; — the  pectoralis  major,  i,  anteriorly; — 
and  the  triangularis  sterni,  i,  posteriorly. 

The  Ribs  are  12  in  number  on  each  side,  7  of  which  are  true  ribs,  being 
each  connected  to  the  sternum  by  a  separate  cartilage; — and  5  are  false 
ribs.  Three  of  the  latter  are  connected  by  their  cartilages  to  the  cartilage 
of  the  7th  rib  (n),  while  two  are  called  floating  ribs  (10),  having  each  one 
extremity  free. 

Characteristics  Common  to  most  of  the  Ribs.  Each  rib  consists  of 
a  head,  neck  and  shaft,  and  presents  the  following  points,  viz. — 


THE   PELVIS  9 

Head, — is  divided  by  a  ridge  into  2  facets,  which  articulate  with  the 
facets  on  the  bodies  of  the  dorsal  vertebrae,  the  lowermost  facet  is 
always  slightly  the  larger;  the  ridge  giving  attachment  to  the  inter- 
articular  ligament. 

Neck  about  an  inch  long,  presents  on  its  upper  border  a  crest  which 
affords  attachment  to  the  ligamentum  costo-transversarium  anterius 
(superior  costo-transverse),  to  its  posterior  surface  the  middle  costo- 
transverse  ligament  (1.  colli  costae),  its  anterior  surface  is  smooth. 

Tuber osity, — at  the  junction  of  the  neck  with  the  shaft,  has  a  facet  for 
articulation  with  the  transverse  process  of  the  next  lower  vertebra, 
and  a  rough  surface  for  the  posterior  costo-transverse  ligament 
(1.  tuberculi  costae). 

Shaft, — twisted  on  itself,  is  concave  internally,  convex  externally,  its 
upper  border  round  and  smooth,  its  lower  border  grooved  for  the 
intercostal  vessels  and  nerves.  At  its  external  extremity  is  an  oval 
depression  for  the  insertion  of  the  costal  cartilage. 

Angle, — just  in  front  of  the  tuberosity,  is  marked  by  a  rough  line,  to 
which  are  attached  the  muscles  of  the  deep  layer  of  the  back. 

Development.  Each  rib  has  3  centres,  one  each  for  the  head,  shaft, 
ind  tuberosity.  The  last  2  ribs,  having  no  tuberosity,  are  developed 
each  by  2  centres. 

Peculiar  Ribs,  are  the  ist,  2d,  loth,  nth,  and  i2th.  They  respectively 
present  the  following  peculiarities — 

ist  Rib, — is  broad,  short,  not  twisted,  has  no  angle,  only  one  facet  on 
the  head;  but  on  its  upper  surface  are  seen  two  grooves  for  the  subclavian 
artery  and  vein,  and  between  them  a  tubercle  for  the  scalenus  anticus 
muscle. 

2d  Rib, — is  not  twisted,  its  tuberosity  and  angle  are  very  close  together, 
and  its  upper  surface  presents  rough  surfaces  for  the  serratus  magnus 
and  scalenus  posticus  muscles. 

loth  Rib, — has  but  one  facet  on  its  head. 

nth  Rib, — has  no  neck,  no  tuberosity,  and  but  one  facet  on  its  head. 

i2th  Rib, — has  neither  neck,  angle,  tuberosity  nor  groove,  and  but  one 
facet  on  its  head. 

THE  PELVIS 

The  Pelvis  is  formed  by  the  sacrum,  os  coccygis  (coccyx),  and  two  ossa 
innominata  (coxae)  and  is  divided  into, — the  pelvis  major  (false  pelvis), 
comprising  the  upper  and  expanded  portion, — and  the  pelvis  minor 
(true  pelvis),  below  the  ilio-pectineal  line  (linea  arcuata).  The  false 


10 


HUMAN   ANATOMY 


FIG.  4. 


pelvis  corresponds  to  the  iliac  fossae  (i),  and  is  marked  by  its  walls  being 
deficient  anteriorly  between  the  iliac  borders,  and  posteriorly  between  the 
sacrum  and  the  posterior  iliac  spines.  The  true  pelvis  has  a — 

Brim,  or  inlet  (apertura  pel  vis  minor  superior), — bounded  in  front  by 
the  crest  and  spine  of  the  pubes  (7),  behind  by  the  promontory  of 
the  sacrum  (15),  laterally  by  the  ilio-pectineal  line  (linea  arcuata). 
Its  axis  corresponds  to  a  line  intersecting  the  umbilicus  and  the  middle 
of  the  coccyx  (os  coccygis).  Its  average  diameters  in  the  female 
are, — 4  inches  antero-posteriorly,  over  5  inches  transversely,  under  5 

inches  obliquely.  In  the 
male  each  of  these  meas- 
urements is  about  %  an 
inch  less. 

Cavity, — is  a  short  curved 
canal,  connecting  the 
brim  with  the  outlet. 
In  front  its  depth  is  about 
i%  inches,  posteriorly  4 
to  4^  inches  in  the 
female,  4^  to  5^  inches 
in  the  male.  Its  diameter 
is  about  4%  inches  in  the 
female,  4>£  inches  in  the 
male,  all  around. 

Outlet  (apertura  pelvis  minor  inferior), — is  bounded  by  the  pubic  arch 

above  (n),  the  tip  of  the  coccyx   (os  coccygis)   behind,  and  the 

tuberosities  of  the  ischia  (9)  laterally.     Its  axis,  if  prolonged,  would 

touch  the  promontory  of  the  sacrum.     Its  diameters  in  the  female  are 

each  about  4^  inches,  in  the  male  about  3^  inches. 

Chief  Differences  between  the  male  and  female  pelves.     The  male 

pelvis  is  marked  by  strength  of  the  bones,  prominence  of  the  muscular 

impressions,  a  deep  and  narrow  cavity,  and  large  obturator  foramina. 

The  female  pelvis  has  lighter  bones,  broader  iliac  fossae,  the  spines  being 

further  apart,  greater  diameters  at  every  point,  the  sacrum  less  curved, 

and  the  pubic  arch  wider. 

The  Sacrum,  or  sacred  bone,  is  triangular,  curved,  with  its  convexity 
backward,  and  is  situated,  base  upwards,  between  the  ossa  innominata 
(coxae)  forming  with  the  coccyx  the  posterior  wall  of  the  pelvis.  The  bone 
consists  of  a  central  portion  (4)  which  consists  of  the  coalesced  bodies 
of  five  vertebrae,  and  on  each  side  a  pars  lateralis  (lateral  mass)  or  ala  (wing) 


THE   PELVIS 


II 


FIG.  5. 


which  is  made  by  the  fusion  of  the  transverse  processes  and  what  might 
be  called  "pelvic  ribs."  Therefore  the  pars  lateralis  presents  a  trans- 
verse portion  and  a  costal  or  alar  portion.  The  sacrum  presents  the 
following  points,  viz. — 

Ridges  (cristae  sacral es  articulares)  (4), — four  transversely  across  both 
surfaces,  mark  the  union  of  its  original  seg- 
ments. 

Anterior  Sacral  Foramina, — eight  for  the   an- 
terior sacral  nerves. 

Grooves  (5), — eight  shallow  and  broad,  for  the 
aforesaid  nerves. 

Promontory, — at  its  junction  with  the  last  lum- 
bar vertebrae. 

Posterior  Sacral  Foramina, — eight    for  the  pos- 
terior sacral  nerves. 

Tubercles, — representing   the  spinous  processes 
of  the  segments. 

Groove, — posteriorly,  on  each  side  of  the  spinous  tubercles. 

Cornua, — two  at  the  posterior  inferior  portion  of  the  bone. 

Articular  Surface  (3), — on  each  side,  articulates  with  the  ilium. 

Notch, — laterally  and  inferiorly,  for  the  5th  sacral  nerve. 

Base  (2), — has  all  the  characteristics  of  the  lumbar  vertebrae,  with  the 
last  of  which  it  articulates. 

Apex  (16), — has  an  oval  surface  for  articulation  with  the  coccyx. 

Sacral  Canal, — the  continuation  of  the  spinal  canal,  is  incomplete  pos- 
teriorly at  its  lower  end.  It  transmits  the  Cauda  Equina;  into  it 
open  the  sacral  foramina  laterally. 

The  Coccyx  consists  of  4  (or  5)  rudimentary  caudal  vertebrae  coalesced 
FlG  6  into  a  triangular  bone,  the  base  (i)  of  which  articu- 

lates with  the  apex  of  the  sacrum.  Its  posterior  sur- 
face is  rough  for  muscles  and  ligaments,  its  anterior 
surface  is  smooth  and  marked  by  ridges  at  the  junction 
of  its  constituent  vertebrae.  It  presents  the  following 
points: — 

Cornua  (2), — two    superiorly,,  articulating    with    the 
sacral  cornua  to  form  foramina  for  the  5th  sacral  nerves. 
Apex, — is  sometimes  bifid  and  turned  to  one  side. 

The   Ossa  Innominate   (coxae),   are  placed   one  on  each  side  of  the 
osseous    pelvis,    and   are   each   formed   by    the   union,  about  puberty, 


12  HUMAN    ANATOMY 

of  3  bones, — the  ilium,  ischium,  and  pubes.     The  innominate  (os  coxae) 
as  a  whole  presents  the  following  points,  viz. — 

It  is  a  large  flat  bone,  constricted  in  the  middle,  and  twisted  upon  its 
long  axis,  so  that  the  expanded  portion  (iliac)  above  the  constriction  is  in 
a  plane  almost  at  right  angles  to  that  of  the  expanded  portion  (ischio- 
pubic)  below.  It  presents  an  outer  surface,  an  inner  surface,  and  a  con- 
tinuous border  which  is  circumferential.  Beginning  at  its  upper  part  the 
border  of  the  os  coxae  (innominate  or  hip  bone),  it  presents  a  crest  (i), 
and,  continuing  forwards  and  around,  the  anterior  superior  spine  (2), 
a  shallow  notch,  the  anterior  inferior  spine  (4),  a  smaller  notch,  the  ilio- 
pectineal  eminence  (5),  superior  (ascending)  ramus  or  body  of  the  ossis 
pubis,  pubic  tubercle  (spine)  and  crest  of  pubis  (9),  the  symphysis  ossis 
pubis,  the  ischio-pubic  ramus  (9),  constituted  in  front  by  the  inferior  (hori- 
zontal or  descending)  ramus  of  the  pubis  and  behind  by  the  ramus  of  the 
ischium,  the  tuber  ischiadicum  (tuberosity  of  the  ischium)  12,  the  lesser 
sciatic  (sacro-sciatic)  notch  (13),  the  ischial  spine  14,  the  greater  sciatic 
(sacro-iliac)  notch  (16),  the  posterior  inferior  spine  of  the  ilium  (17),  and 
lastly  the  posterior  superior  spine  of  the  ilium.  The  inner  surface  is  divided 
by  the  ilio-pectineal  line  into  an  upper  portion  and  a  lower  portion.  The 
upper  portion  (false  pelvis)  presents  in  front  the  iliac  fossa,  and  behind,  the 
articular  (auricular)  surface  and  a  rough  surface  for  the  posterior  sacro- 
iliac  ligament.  The  lower  part  of  the  inner  surface  (true  pelvis)  presents 
the  obturator  groove  and  the  obturator  foramen  (8).  In  addition  to 
what  is  described  with  the  ilium,  ischium  and  pubes,  the  outer  surface 
presents : — 

Acetabulum,  or  cotyloid  cavity, — receives  the  head  of  the  femur.  It  is 
situated  at  the  junction  of  the  3  bones  externally,  the  ilium  and 
ischium  each  forming  about  two-fifths,  and  the  pubic  bone  one-fifth 
of  it.  A  depression  in  its  centre  lodges  a  mass  of  fat  containing 
vessels  for  the  nourishment  of  the  synovial  membrane.  The  Cotyloid 
Notch  (Incisura  Acetabuli)  is  a  deficiency  in  its  lower  margin,  trans- 
mitting nutrient  vessels  to  the  joint;  to  the  edges  of  the  notch  is 
attached  the  ligamentum  teres,  and  it  is  bridged  over  by  the  trans- 
verse ligament,  a  continuation  of  the  cotyloid  ligament  (labrum 
glenoidale)  which  surmounts  the  brim  of  the  acetabulum.  Crossing 
the  ischium  horizontally,  immediately  below  the  acetabulum,  is  a 
deep  groove  for  the  obturator  externus  tendon. 

Obturator  or  Thyroid  Foramen  (8), — on  the  anterior  surface  between  the 
pubes  and  ischium,  large  and  oval  in  the  male,  small  and  triangular 
in  the  female;  is  closed  by  the  obturator  membrane,  except  above 


THE   PELVIS  13 

at  the  obturator  canal  or  groove  where  the  obturator  nerves  and 

vessels  pass  through. 

The  Ilium  is  the  superior  part  of  the  innominate  bone,  its  outer  surface 
presents  the  following  points,  viz. — 

Crest  (i), — along  its  upper  border,  having  an  outer  and  inner  lip  for 

muscular  attachment,  and  ending  in  the  superior  spines. 
Anterior  Superior  Spine  (2), — to  which  are  attached  the  sartorius  and 

tensor  fasciae  (vaginae)  femoris  muscles  and  the  inguinal  (Poupart's) 

ligament. 

Anterior  Inferior  Spine  (4), — for  the  straight  tendon  of  the  rectus  femoris. 
Notch,   between    the    above-named   spines, 

transmitting    the    external    (lateral)    cu- 
taneous  nerve,   and  lodging   some  fibres 

of  the  sartorius. 

Posterior  Superior  Spine  (19), — for  the  at- 
tachment   of    the    erector  spinae  muscle, 

and  the  oblique  part  of  the  sacro-iliac 

ligament. 
Posterior  Inferior  Spine  (17), — for  the  sacro- 

tuberous  (great  sacro-scia tic)  ligament. 
Great    Sciatic    (Sacro-iliac)    Notch     (16), — 

below    the    last-named    spine,   transmits 

the    great   sciatic,  superior   gluteal,    and 

pudic  (pudendal)   nerves,  the  pyriformis 

muscle,  and  the  sciatic,  pudic  (pudendal)  and  gluteal  vessels,  also  a 

nerve  supplying  the  obturator  externus  muscle. 
Gluteal  ridges  (Curved  Lines)  (21)  posterior,  anterior,  and  inferior,  on 

the  outer  surface  of  the  bone,  from  the  spaces  between  which  arise 

the  glutei  muscles. 
Groove, — above  the  acetabulum,  for  the  reflected  tendon  of  the  rectus 

femoris  muscle. 

The  Ischium  is  the  lowermost  portion  of  the  os  coxae  (innominate  bone), 
and  presents  the  following  points,  viz. — 

B ody  (superior  ramus), — forms  two-fifths  of  the  acetabulum,    and  the 

external  margin  of  the  obturator  foramen;  on  it  is  a  broad  groove  for 

the  tendon  of  the  obturator  externus  muscle.     Its  posterior  margin 

assists  in  forming  the  great  sciatic  (sacro-sciatic)  notch. 
Spine  (14), — for  the  gemellus  superior,   coccygeus,   and  levator  ani 

muscles,  and  the  lesser  sacro-sciatic  ligament. 
Lesser  Sciatic  (Sacro-sciatic}  Notch  (13) — below  the  spine,  transmits  the 


14  HUMAN    ANATOMY 

obturator  muscle,  its  nerve,  and  the  pudic  vessels  and  nerve  as 
they  re-enter  the  pelvis,  having  crossed  the  spine  of  the  ischium. 
The  sacro-sciatic  notches  are  converted  into  foramina  by  the  sacro- 
sciatic  ligaments;  the  greater  notch  by  the  lesser  ligament  (sacro- 
spinous),  the  lesser  notch  by  the  greater  ligament  (sacro-tuberous). 

Tuberosity  (12), — the  lowest  and  most  prominent  part,  gives  attach- 
ment to  the  greater  sacro-sciatic  (sacro-tuberous)  ligament,  and  to 
several  muscles.  On  it  one  rests  when  sitting. 

Horizontal  Ramus  (inferior  ramus), — bounds  the  obturator  foramen 
inferiorly,  articulates  with  the  (descending)  (inferior)  ramus  of  the 
pubes,  and  gives  attachment  to  the  obturator  membrane  and  several 
muscles. 

The  Pubes.  The  pubic  or  pectineal  bone  forms  the  anterior  portion 
of  the  innominate.  It  presents  the  following  points,  viz. — 

Body, — with  its  fellow  forms  the  Symphysis,  giving  origin  to  several 
muscles  and  ligaments. 

Crest  (9), — on  the  upper  part  of  the  body,  terminates  externally  in  the 
spine. 

Spine, — affords  attachment  to  one  end  of  inguinal  (Poupart's)  ligament. 

(Linea  Ilio-pectinea),  (pecten  ossis  pubis)  in  part, — gives  attachment  to 
the  conjoined  tendon,  Gimbernat's  (lacunar)  ligament,  and  the  tri- 
angular ligament. 

Horizontal  Ramus, — forms  part  of  the  margin  of  the  obturator  fora- 
men, and  of  the  acetabulum. 

Pectineal  Eminence  (5), — gives  attachment  to  the  psoas  parvus  muscle. 

Muscles  attached  to  the  hip  bone  number  36,  comprising  those  of 
the  abdomen,  thigh,  perineum,  floor  of  the  pelvis,  and  rotators  of  the 
hip-joint. 

THE   BONES   OF   THE   HEAD 

THE  FRONTAL  BONES  (OS  FRONTALE),  (i,  Fig.  8) 

Points  on  its  Frontal  (Vertical)  Portion,  are  as  follows: — 
Externally, — An  upper  angle  (6), — Lateral  angles  (12), — • 
Frontal  Eminences  (tuberosities) , — one  on  each  side  of  the  median  line. 
Depression, — marking  the  site  of  the  frontal  (metopic)  suture  before 

obliteration. 

Superciliary  Arches  (Ridges), — behind  which  are  the  frontal  sinuses. 
Supraorbital  Notches  or  Foramina, — in  the  supraorbital  arches,  at  about 

their  inner  third,  for  the  supraorbital  vessels  and  nerves. 
Nasal  Eminence  (24), — at  lower  end  of  the  frontal  depression. 


THE    FRONTAL  BONE  15 

External  Angular,  (Lateral   or   Zygomatic)   Processes    (13), — articulate 

with   the   malar   (zygomatic)    bones    and    form    the    anterior   part 

of  the  temporal  ridges. 
Internal  (Medial)    Angular   Processes, — articulate    with    the    lacrimal 

bones. 
Nasal   (Frontal)    Spine    and    Notch, — between    the  internal   angular 

processes. 
Internally, — 

Sagittal  Sulcus  or  Groove, — for  superior  longitudinal   sinus  and   the 

falx  cerebri. 

Frontal  Crest, — for  attachment  of  the  falx  cerebri. 
Foramen  Coecum, — for  a  small  vein  to  the  longitudinal  sinus. 

FIG.  8. 


Depressions  and  Elevations, — for  convolutions  of  the  brain. 
Between  the  two  tables  of  the  vertical  portion  in  the  adult  are  the — 
Frontal  Sinuses, — two  spaces  at  the  anterior  inferior  part  of  the  bone, 
which  are  lined  with  mucous  membrane,  and  open  into  the  middle 
meatus  of  the  nose. 

The  Orbital  Plates  (Pars  Orbitalis).     Each  plate  presents  the  following 
points, — 

Fossa, — for  the  lacrimal  gland,  near  the  external  angular  process. 
Fovea  Trochlearis, — a  depression  at  the  nasal  margin  for  the  pulley  of 
the  superior  oblique  muscle. 


1 6  HUMAN   ANATOMY 

Ethmoidal  Notch, — having  the  following  foramina  on  its  margin. 
Anterior  Ethmoidal  Foramen, — for  the  anterior  ethmoidal  vessels  and 

the  naso-ciliary  branch  of  the  ophthalmic  nerve. 
Posterior  Ethmoidal  Foramen, — for  posterior  ethmoidal  vessels. 
Grooves, — on  the  cranial  surface,  for  branches  of  the  anterior  and  middle 

meningeal  arteries. 

Articulations,  Development,  and  Muscles.  Each  half  of  the  frontal 
bone  articulates  from  its  upper  angle  to  its  lateral  angle,  with  the  parietal, — 
from  lateral  angle  to  zygomatic  process,  with  the  front  part  of  the  apex  of 
the  Great  Wing  of  the  sphenoid, — zygomatic  process,  with  the  malar, — 
posterior  border  of  orbital  plate,  with  Lesser  Wing  of  the  sphenoid,  mar- 
gins of  ethmoidal  notch  with  the  ethmoid, — medial  border  of  the  orbital 
plate  from  behind  forwards,  with  orbital  plate  of  ethmoid, — lacrimal, 
nasal  process  of  maxilla, — frontal  spine,  with  the  nasal.  It  is  developed  by  2 
centres  in  membrane,  i  for  each  lateral  half.  The  muscles  attached  to 
it  are  3  pairs, — the  temporal,  corrugator  supercilii,  and  orbicularis  palpe- 
brarum. 

THE  PARIETAL  BONES,  (2,  Fig.  8) 

General  Characteristics.  They  are  2  quadrilateral  bones  situated 
at  the  superior  and  lateral  regions  of  the  cranium.  Each  has  a  frontal 
(anterior  superior)  angle  (6),  anterior  border,  sphenoidal  (anterior 
inferior)  angle  (10),  a  lower  border,  a  truncated  mastoid  (posterior 
inferior)  angle  (9),  a  posterior  border,  an  occipital  (posterior  superior) 
angle  (7),  and  an  upper  border.  The  articulations  are, — the  superior 
border  of  each  joins  the  other  by  the  Sagittal  Suture;  the  anterior  border 
joins  the  frontal  bone  forming  the  Coronal  Suture  (6) ;  the  posterior  border 
articulates  with  the  occipital,  forming  the  Lambdoid  Suture  (7);  the  inferior 
border  from  before  backwards  with  the  great  wing  of  the  sphenoid  (5), 
squamous  and  mastoid  portions  of  the  temporal  (4).  Forming  the  lateral 
walls  of  the  skull  they  are  named  parietal,  from  paries,  a  wall. 

Points  on  each  Parietal  Bone.  Externally  the  bone  is  convex  and  pre- 
sents for  examination, — 

Temporal  Ridge  (13), — continuous  with  the  same  on  the  frontal  bone, 
bounded  above  by  the  superior  temporal  line,  and  below  by  the  in- 
ferior temporal  line. 

Parietal  Eminence  (tuberosity) , — the  point  where  ossification  com- 
menced. 

Parietal  Foramen, — close  to  the  upper  border,  transmits  an  emissary 


THE    OCCIPITAL  BONE  IJ 

vein  to  the  superior  longitudinal  (sagittal)  sinus.     Is  not  constant. 

Internally,  the  bone  is  concave,  and  marked  by — • 
Depressions, — for  the  Arachnoideal  Granulations  (Pacchionian  bodies), 

and  for  the  cerebral  convolutions. 

Furrows, — for  branches  of  the  middle  meningeal  artery. 
Groove, — for  the  lateral    (transverse)    sinus,  at   the   posterior  inferior 

angle. 
Half-groove, — along  the  upper    border,  for    the   superior  longitudinal 

(sagittal)  sinus  of  the  dura  mater. 

Development.     Each  parietal  bone  is  developed  from  i  centre  in  mem- 
brane.    The  only  muscle  attached  to  it  is  the  temporal. 


FIG.  9. 


THE  OS  OCCIPITALE,  (3,  Fig.  8) 

is  a  symmetrical  bone.  Its  border  presents  an  upper  angle,  and  on  each 
side,  lateral  angle,  jugular  process,  jugular  notch,  petrosal  process 
along  the  edge  of  the  basilar  proc- 
ess, and  the  apex  of  the  basilar 
process. 

General  Features  and  Surfaces. 
It  is  trapezoidal  in  form,  curved 
upon  itself,  and  placed  at  the  pos- 
terior and  inferior  region  of  the 
cranium.     Externally  its  surface 
is  convex  and  presents  for  exami- 
nation the  following,  viz. — 
External  Occipital  Protuberance 
(5),  and  Crest  (4),  for  the  at- 
tachment of  the  ligamentum 
nuchae. 

Superior  and   Inferior   Nuchal 
(Curved}     Lines, — extending 
outward  on  each  side  of  the 
external  occipital  crest;  in  one  skull  in  every  six  there  is  to  be  seen 
a  supreme  nuchal  line  above  the  others. 

Foramen  Magnum  (2), — transmitting  the  medulla  oblongata  and  its 
membranes,  the  vertebral  arteries,  and  the  recurrent  portions  of  the 
spinal  accessory  nerves. 

Condyles  (6), — two  in  number,  for  articulation  with  the  atlas. 
Tubercles, — i  on  each  condyle,  for  the  check  ligaments. 


l8  HUMAN   ANATOMY 

Anterior     Condylar    Foramina     (canalis     hypoglossi),— two     for    the 

hypoglossal  nerves. 
Posterior   Condylar    Foramina    (canalis  condyloideus  posterior)  (3), — 

two  (often  absent)  for  emissary  veins. 
Jugular  Processes  (7), — two,  each  partly  bounding  the  foramen  lacerum 

posterius  basis  cranii. 
Jugular  Fossa  (8), — each  forming  part  of  the  foramen  lacerum  posterius 

basis  cranii. 
Internally,  the  surface  is  concave,  showing — 

Fosses, — four  for  the  cerebellar  and  posterior  cerebral  lobes. 

Internal  Occipital  Protuberance, — where  6  cranial  sinuses  meet  to  form 

the  torcular  (wine-press)  Herophili. 

Crucial  Ridge, — the  vertical  portion  for  the  falx  cerebri  and  falx  cerebelli; 
the  transverse  portion  for  the  tentorium  cerebelli,  having  also  a  groove 
for  the  lateral  (transverse)  sinus. 
Groove, — for  the  lateral  (transverse)   sinus,  and  the  inferior  petrosal 

sinus,  along  the  postero-lateral  border. 
Internal  Openings, — of  the  foramina  described  above. 
Basilar  Process  (i)  of  the  Occipital  lies  in  front  of  the  foramen  mag- 
num (2),  articulates  with  the  body  of  the  sphenoid  bone,  smooth  and 
grooved  in  the  mid-line  for  the  medulla  oblongata  and  pons  varolii,  which 
lie  upon  it,  grooved  laterally  by  the  inferior  petrosal  sinuses;  rough  in- 
feriorly  for  the  attachment  of  muscles,  and  presenting  the — 
Pharyngeal  Tubercle  or  Spine, — for  the  attachment  of  the  superior  con- 
strictor muscle  of  the  pharynx  and  its  tendinous  raphe. 
Articulations  and  Development.     The  occipital  articulates  as  follows. — 
The  condyles  articulate  with  atlas,  apex  of  the  basilar  process  with  body 
of  sphenoid,  side  of  basilar  process  and  apex  of  jugular  process  with 
petrous  portion  of  temporal,  from  jugular  to  lateral  angle  with  mastoid 
portion  of  temporal,  from  lateral  angle  to  upper  angle  with  parietal.     It 
is  developed  by  4  centres,  i  each  for  the  posterior  part,  the  basilar  process, 
and  the  2  condyles;  its  ossification  being  completed  about  the  6th  year 
of  age. 

Muscles  attached  to  the  Occipital  Bone.     There  are  12  muscles  at- 
tached on  each  side  to  the  following  portions,  viz. — 

Superior  Nuchal  Line  3, — the  occipito-frontalis,  trapezius,  and  sterno- 

cleido-mastoid  muscles. 

Space  between  the  nuchal  lines  2, — the  complexus  and  splenius. 
Space  below  the  inferior  nuchal  line  3, — the  obliquus  capitis  superior, 
rectus  capitis  posticus  major  and  rectus  capitis  posticus  minor. 


THE    TEMPORAL  BONE 


Basilar  Process  3, — the  superior  constrictor  of  the  pharynx,  rectus  capitis 

anticus  major  and  rectus  capitis  anticus  minor. 
Jugular  Process  i, — the  rectus  capitis  lateralis. 


FIG.  10. 


THE  TEMPORAL  BONES    (OSSA  TEMPORALIA),    (4,  Fig.   8) 

Situation  and  Divisions.  They  are  situated  at  the  inferior  lateral 
portions  of  the  skull,  and  contain  the  organs  of  hearing.  Each  bone  is 
formed  by  the  union  of  three  parts,  namely,  the  Squamous,  Petro-mastoid, 
and  Tympanic. 

The  Squamous  Portion  is  a  semicircular  plate,  smooth  externally,  and 
grooved  internally  for  the  middle 
meningeal   artery,   with    depres- 
sions for    the  cerebral  convolu- 
tions.    Externally  are  seen  the — 
Zygomatic    Process    (d\    or 
Zygoma, — arising  by  3  roots, 
and    extending    forward    to 
articulate    with    the    malar 
bone. 

Zygomatic  Tubercle  (e),  at  the 
base  of  the  process,  for  the 
external  lateral  ligament  of 
the  lower  jaw. 

Anterior  Articular  Ridge  (emi- 
nentia  articularis), — formed 
by  the  anterior  root  of  the  zygoma. 

Mandibular  (Glenoid)  Fossa  (g), — between  the  anterior  and  posterior 
articular  ridge  (middle  root  of  the  zygoma)  for  articulation  with 
the  condyle  of  the  lower  jaw,  and  is  covered  with  cartilage. 
Glaserian  Fissure, — divides  the  squamous  from  the  tympanic;  it  trans- 
mits the  laxator  tympani  muscle,  the  tympanic  artery,  and  lodges 
the  processus  gracilis  of  the  malleus  and  the  inferior  process  of  the 
petrous. 

Opening  of  the  Canal  of  Hugier, — lies  in  the  angle  between  the  squamous 
and  petrous  portions  of  the  bone;  and  transmits  the  chorda  tympani 
nerve. 

Temporal  Ridge  (/), — in  part,  here  known  as  the  suprameatal  ridge. 
THE  PETRO-MASTOID, — is  usually  described  as  consisting  of  a  mastoid 
portion  and  a  petrous  portion. 


20 


HUMAN    ANATOMY 


FIG.   ii. 


The  Mastoid  Portion.  Its  cerebellar  surface  is  grooved  for  the  lateral 
sinus  (9);  externally  it  presents  the  following, — 

Mastoid  Foramen  (h)y — the  largest  of  several  foramina,  for  a  vein. 
Mastoid  Process, — at  the  tip,  for  the  sterno-cleido-mastoid,  splenius,  and 

trachelo-mastoid  muscles. 

Digastric  Fossa  (j}, — for  the  posterior  belly  of  the  digastric  muscle. 
Occipital  Groove  (8), — for  the  occipital  artery. 
The  Mastoid  Cells, — in  the  interior  of  the  mastoid  process,  open  on  the 

posterior  wall  of  the  middle  ear,  and  are  lined  with  mucous  membrane. 

The  Petrous  Portion  is  very  hard,  pyramidal  in  form,  contains  the  in- 
ternal ear,  projects  inward  and  forward,  and  presents  a  base,  an  apex,  a 
cerebral  surface,  cerebellar  surface,  tympanic  surface,  and  basilar  surface; 

upper  border,  anterior  border,  pos- 
terior border;  the  tympanic  bone  is 
blended  with  the  inferior  border  and 
conceals  it. 
On  the  Base  are  seen,  the — 

Meatus  Auditor ius  Externus  (i), — 
the  external  opening  of  the  ear. 
Auditory  Process  of  the  Tympanic, — 
a  bony  ring  for  the  external  car- 
tilage of  the  ear. 

Apex  lies  internally,  at  the  base  of 
the  skull,  forming  the  outer 
boundary  of  the  foramen  lacerum 
medium,  and  contains  the  internal 
carotid  canal. 
CEREBRAL  (Anterior)  Surface,  presents  from  within  outward — 

Inner  Opening  of  the  Carotid  Canal  (n), — for  the  internal  carotid  artery 

and  plexus. 

Depression, — for  the  Gasserian  ganglion  of  the  5th  pair  of  cranial  nerves. 
Hiatus  Canalis  Facialis  or  Hiatus  Fallopii, — for  the  great  petrosal  nerve, 

branch  of  the  middle  meningeal  artery. 
Foramen, — for  the  small  petrosal  nerve. 
Eminence, — over  the  superior  semicircular  canal  of  the  ear. 
Depression, — over  the  tympanum. 
Cerebellar  (Posterior)  Surface  presents, — 

Meatus  Auditorius  Internus  (12), — transmits  the  yth  and  8th  pairs  of 
cranial  nerves  and  the  auditory  artery,  and  lodges  a  process  of  dura 


THE   TEMPORAL  BONE  21 

Opening  of  the  Aqu&ductus  Vestibuli  (13), — transmits  to  the  vestibule  a 

small  artery  and  vein,  and  lodges  a  process  of  dura  mater. 
Basilar  (Inferior)  surface,  presents  from  within  outward — 

Rough  Quadrilateral  Surface  (19), — for  the  origin  of  the  tensor  tympani 

and  levator  palati  muscles. 
Opening  of  the  Carotid  Canal, — transmitting  the  internal  carotid  artery, 

and  the  carotid  plexus  of  the  sympathetic  nerve. 

Aqu&ductus  Cochlea, — transmitting  an  artery  and  vein  to  the  cochlea. 
Jugular  Fossa, — a  depression  for  the  sinus  of  the  internal  jugular  vein, 
forming  with  the  occipital  bone  the  foramen  lacerum  posterius,  which 
transmits  that  vein  and  the  8th  pair  of  cranial  nerves,  etc. 
Foramen  for  Jacobson's  Nerve  (tympanic  branch  of  the  glossopharyn- 
geal), — in  the  ridge  between  the  jugular  fossa  and  the  carotid  canal. 
Foramen  for  Arnold's  Nerve  (auricular  branch  of  the  pneumogastric), — 

in  the  outer  wall  of  the  jugular  fossa. 

Jugular  Surface, — for  articulation  with  the  jugular  process  of  the  occi- 
pital bone.  The  Tympanic  Surface  can  be  seen  by  looking  in  the 
external  auditory  canal,  forms  most  of  the  osseous  wall  of  the  middle 
ear  or  tympanum.  It  presents  the  Promontory  of  the  Cochlea, 
Fenestra  Vestibuli,  and  Fenestra  Cochlea. 

The  Tympanic  Bone  forms  most  of  the  external  auditory  canal.  Its 
under  surface  is  slightly  concave,  forming  a  fossa  for  part  of  the  parotid 
gland.  It  presents  a  sharp  ridge  which  projects  downwards,  and  forms 
the,— 

Vaginal  Process  (1), — ensheathing  the  root  of  the  styloid  process. 
Styloid  Process  (14), — a  long  projection  for  the  stylo-pharyngeus,  stylo- 
hyoid,   and  stylo-glossus  muscles;  and  the  stylo-hyoid  and  stylo- 
mandibular  ligaments,  which  are  attached  thereto. 
Stylo-mastoid  Foramen  (15), — between  the  styloid  and  mastoid  processes, 
for  the  exit  of  the  facial  nerve,  and  the  entrance  of  the  stylo-mastoid 
artery. 
Auricular  Fissure, — for  the  exit  of  the  auricular  branch  of  the  vagus 

(Arnold's  nerve). 

In  the  angle  between  the  petrous  and  squamous  portions,  are  seen  the — 
Septum  Tuba, — a  lamina  separating  the  following  canals.     Its  inner  end 
projects  into  the  tympanum,  and  is  called  iheProcessus  cochleariformis. 
Opening, — of  the  canal  for  the  tensor  tympani  muscle. 
Osseous  Opening, — of  the  Eustachian  tube  (n)  inferiorly. 
The    Anterior    Border   articulates   partly    with    the  alar  spine  of  the 
sphenoid  bone. 


22  HUMAN   ANATOMY 

The  Posterior  Border  assists  in  forming  the  jugular  foramen,  and  is  grooved 

for  the  inferior  petrosal  sinus. 
The  Superior  Border  separates  the  anterior  fossa  of  the  skull  from  the 

middle  fossa;  to  it  is  attached  the  tentorium  cerebelli,  and  it  is  grooved 

for  the  superior  petrosal  sinus  (10),  and  in  infants  it  presents  afloccular 

fossa. 

Articulations  and  Development.  The  temporal  articulates  as  follows, — 
Anterior  border  of  the  petrous  and  squamous  with  the  great  wing  of  the 
sphenoid, — upper  border  of  the  squamous  and  mastoid  with  the  parietal, — 
posterior  border  of  the  petro-mastoid  with  the  occipital, — apex  of  zygo- 
matic  process  with  malar,  and  indirectly  the  glenoid  fossa  with  the 
mandible.  It  is  developed  by  4  principal  centres,  one  each  for  the  squamous 
portion,  styloid  process,  and  tympanic,  and  one  for  the  petro-mastoid 
portions.  Its  ossification  is  completed  about  the  2d  or  3d  year. 

Muscles  attached  to  it.  There  are  14  muscles  attached  to  the  following- 
named  portions.  To  the — 

Squamous  Portion  2, — the  temporal  and  masseter. 

Mastoid  Portion  6, — the  occipito-frontalis,  sterno-cleido-mastoid,  splen- 
ius  capitis,  trachelo-mastoid,  digastric,  and  retrahens  aurem. 

Petrous  Portion  3, — the  tensor  tympani,  levator  veli  palatini  (leva tor 
palati)  and  stapedius. 

Styloid  Process  3, — the  stylo-glossus,  stylo-hyoid,  and  stylo-pharyngeus. 

THE  SPHENOID  BONE,  (5,  Fig.  8) 

Position  and  Form.  Wedged  in  between  the  bones  of  the  skull  ante- 
riorly, it  resembles  a  bat  with  out-stretched  wings.  It  is  named  from  the 
Greek  word  <r^v,  a  wedge,  enters  into  the  formation  of  5  cavities,  4  fossae, 
3  fissures,  and  presents  for  description — 

Body  of  the  Sphenoid  Bone.  Placed  in  the  median  line,  cuboid  in  shape, 
it  presents  on  its  UPPER  SURFACE  from  before  backward,  the  following 
points, — 

Sphenoidal  or  Ethmoidal  Spine  (3), — articulating  with  the  ethmoid  bone. 

Smooth  Surface, — grooved  for  the  olfactory  nerves. 

Sulcus  Chiasmatis  or  Optic  Groove, — supporting  the  commissure  of  the 
optic  nerves. 

Tuberculum  Settee  or  Olivary  Process, — an  olive-shaped  eminence  behind 
the  optic  groove. 

Middle  Clinoid  Processes, — bounding  the  Sella  Turcica  in  front. 

Fossa  Hypophyseos  or  Sella  Turcica  (16)  (Turkish  saddle),  lodges  the 
hypophysis  (pituitary  body)  and  the  circular  sinus  of  the  brain. 


THE   SPHENOID  BONE  23 

Dorsum  Sella  (cantle  of  the  saddle)  (16), — grooved  for  the  6th  nerves. 
Posterior  Clinoid  Processes  (6), — for  attachment  of  the  tentorium  cere- 
belli,  grooved  by  the  optic  tracts. 

FIG.  12. 


Grooves, — laterally,  for  the  cavernous  sinus  and  internal  carotid  artery. 
POSTERIOR  SURFACE  is  rough  and  quadrilateral  (15) :  it  articulates  with  the 
basilar  process  of  the  occipital  bone,  ossification  being  completed  from 
the  1 8th  to  the  2oth  year  of  age. 

FIG.  13. 


ANTERIOR  SURFACE  is  nearly  vertical,  and  presents  the — 

Sphenoidal  crest, — in  the  median  line,  articulating  with  the  perpendicu- 
lar plate  of  the  ethmoid  bone,  and  forming  part  of  the  nasal  septum- 
Openings  of  the  Sphenoidal  Sinuses  (e), — cavities  in  the  body  of  the  bone 
which  exist  in  adults,  not  in  children. 


24  HUMAN   ANATOMY 

Sphenoidal  Concha  or  Sphenoidal  Turbinal  Bones, — which  partially  close 

the  sinuses,  and  articulate  with  the  ethmoid  and  orbital  processes  of 

the  palate  bones. 

INFERIOR  SURFACE  helps  to  form  the  nasal  fossae,  and  presents  the — 
Rostrum  (d), — which  articulates  with  a  groove  on  the  vomer. 
Alar  Grooves, — on  each  side  of  the  rostrum,  for  articulation  with  the 

wings  of  the  vomer. 

Vaginal  Processes, — i  on  each  side  of  the  rostrum. 
Pterygo-palatine  Grooves, — which,  with  the  sphenoidal  processes  of  the 

palate  bones,  form  the  pterygo-palatine  canals,  for  the  transmission 

of  the  pterygo-palatine  arteries  and  nerves. 

Greater  Wings  of  the  Sphenoid.  Each  wing  presents  on  its  CEREBRAL 
SURFACE  the  following  points, — 

Foramen  Rotundum  (8), — for  the  maxillary  division  of  the  5th  nerve. 
Foramen  Ovale  (9), — for  the  mandibular  division  of  the  5th  nerve,  the 

small  petrosal  nerve,  and  small  meningeal  artery. 
Foramen  Vesalii, — transmitting  a  small  vein;  often  absent. 
Foramen  Spinosum  (10), — transmitting  the  middle  meningeal  artery 

and  veins,  also  sympathetic  filaments  from  the  cavernous  plexus. 
THE  ORBITAL  or  ANTERIOR  SURFACE  assists  in  forming  the  external  wall  of 
the  orbit,  the  inferior  orbital  (spheno- maxillary)  and  superior  orbital 
(sphenoidal)     fissures.     It    articulates    with    the  frontal  and  malar 
bones,  and  presents  a — 

Notch, — transmitting  a  branch  of  the  ophthalmic  artery. 
Spine, — for  part  of  the  lower  head  of  the  external  rectus  muscle. 
External  Orbital  Foramina, — transmitting  nutrient  arterial  branches. 
EXTERNAL  SURFACE  consists  of  an  upper  portion,  the  temporal,  separated 
by  a  ridge,  the  infra-temporal  crest,  from  a  lower  portion,  the  spheno- 
maxillary  surface.     It  presents  the  following  points, — 
Infra-temporal  or  Pterygoid  Ridge, — dividing   the  temporal  fossa  from 

the  spheno-maxillary. 
Alar  Spine  of  the  Sphenoid  (n),— to  which  are  attached  the  internal 

lateral  ligament  of  the  lower  jaw,  and  the  laxator  tympani  muscle. 
CIRCUMFERENCE  is  partly  serrated  for  articulation  with  the  temporal  and 
frcntal  bones,  and  partly  smooth  for  the  anterior  margin  of  the  foramen 
lacerum  medium  and  the  inferior  margin  of  the  superior  orbital  (sphe- 
noidal) fissure,  which  margins  it  assists  in  forming. 

Lesser  Wings  (i)  of  the  Sphenoid,  or  the  Processes  of  Ingrassias  (a), — 
terminate  internally  in  the  Anterior  Clinoid  Processes  (5);  their  anterior 
borders  articulate  with  the  orbital  plate  of  the  frontal  bone,  the  posterior 


THE    SPHENOID  BONE  25 

are  free,  dividing  the  anterior  cerebral  fossa  from  the  middle  ones.     Con- 
nected intimately  with  each  of  these  wings  are  the — 

Optic  Foramen  (4) , — formed  by  the  separation  of  its  roots,  and  transmit- 
ting the  optic  nerve  and  the  ophthalmic  artery. 

Superior  Orbital  or  Sphenoidal  Fissure  (7),  or  Foramen  Lacerum 
Anterius  (g), — is  bounded  above  by  the  lesser  wing,  below  by  the 
greater  wing,  and  transmits  the  3d,  4th,  ophthalmic  division  of  the 
5th,  and  the  6th  nerves,  the  ophthalmic  vein,  branches  of  the  lacri- 
mal  and  middle  meningeal  arteries,  some  filaments  of  the  sympathetic 
and  a  process  of  the  dura  mater. 

Medial  (Internal)  and  Lateral  (External)  Pterygoid  Processes  of  the 
Sphenoid.  These  wing-like  processes  descend,  i  on  each  side  of  the  body, 
and  divide  each  into  2  thin,  bony  plates  (/w),  connected  together  anteriorly, 
and  presenting  the — • 

Pterygoid  Fossa, — between  the  plates  posteriorly,  the  origin  of  the  inter- 
nal pterygoid  muscle. 
Scaphoid  Fossa, — at  the  base  of  the  internal  plate,  serves  as  the  origin  of 

the  tensor  veli  palatini  (tensor  palati)  muscle. 
Hamular  Process, — a  hook-like  projection  at  the  apex  of  the  internal 

plate,  around  which  plays  the  tendon  of  the  tensor  palati  muscle. 
Canalis  Pterygoideus  or  Vidian  Canal  (14), — at  the  root  of  the  process, 

for  the  Vidian  nerve  and  vessels. 

Triangular  Notch, — at  the  end  of  the  process,  articulates  with  the  tu- 
berosity  of  the  palate  bone. 

Development  of  the  Sphenoid.  By  14  or  1 6  centres,  as  follows, — 2  for 
the  greater  wings,  2  for  the  lesser  wings,  2  for  the  anterior  part  of  the  body, 
2  for  the  posterior  part  of  the  body,  2  for  the  medial  (internal)  pterygoid 
processes,  and  2  for  the  sphenoidal  conchae  (turbinal  processes),  2 
for  the  lingulae  and  2  for  the  epipteric  bones  which  usually  join  the  tips 
of  the  great  wings.  Ossification  begins  in  the  2d  fcetal  month,  and  is 
completed  about  the  nth  year,  by  the  union  of  the  turbinal  processes 
with  the  body. 

Muscles  attached  to  the  Sphenoid. — 12  pairs  of  muscles  are  attached 
to  the  sphenoid  bone,  as  follows: — 

Orbital  muscles,  6 — all  except  the  inferior  oblique  of  the  eye. 

Muscles  of  Mastication,  3 — the  temporal,  external  and  internal  ptery- 

goids. 
Also  the  superior  constrictor,  tensor  palati,  and  laxator  tympani,  3. 


26  HUMAN   ANATOMY 

THE  ETHMOID  BONE 

General  Characteristics.  It  is  a  spongy,  light  bone,  depending  from 
the  ethmoidal  notch  of  the  frontal,  and  from  between  its  orbital  plates.  It 
consists  of  a  body  and  2  lateral  masses,  and  is  named  from  the  Greek 
word  r/0/zos,  a  sieve. 

Points  on  its  Body.  The  body  (b)  consists  of  a  horizontal  or  cribriform 
plate  and  presents  the — 

Crista  Galli  (c) , — or  cock's  comb,  projecting 
upward,  for  the  attachment  of  the  anterior 
end  of  the  falx  cerebri. 
Cribriform  Plate  (d), — on  each  side  of  the 
crista  galli.  It  is  concave  for  the  olfac- 
tory bulbs  (/),  and  perforated  for  the 
transmission  of  the  olfactory  nerves,  the 
nasal  branch  of  the  ophthalmic  nerve, 
and  numerous  small  vessels. 
Perpendicular  Plate  (a), — assists  to  form 
the  nasal  septum,  is  usually  inclined  to 
one  side,  grooved  for  filaments  of  the  olfac- 
tory nerves,  and  has  attached  to  it  the  car- 
tilage of  the  nose. 

Lateral  Masses.  They  consist  of  a  number  of  cellular  cavities,  and  each 
^ne  presents  the  following  points, — 

Ethmoid  Cells, — the  anterior  opening    by  the  infundibulum  into  the 

middle  meatus  of  the  nose,  the  posterior  into  the  superior  meatus. 
Orbital  Plate  (lamina  papyracea,  os  planum)  (h), — helps  to  form  the 
inner  wall  of  the  orbit  and  is  notched  superiorly  to  form  with  the 
frontal  bone  the  two  ethmoidal  foramina,  or  grooves. 
Uncinate,  or  Unciform  Process, — descends  to  articulate  with  the  infe- 
rior concha,  or  turbinal,  and  forms  part  of  the  inner  wall  of  theantrum. 
Superior  Concha,  or   Turbinal    Process  (/),- — is  a  subdivision  of  the 

posterior  part  of  the  middle  turbinal  process. 

Middle  Concha,  or  Turbinal  Process  (g), — is  larger  and  more  curved 
than  the  superior.  These  processes  bound  the  superior  meatus  of 
the  nose. 

Articulations,  Development,  and  Muscles.  The  ethmoid  articulates 
with  15  bones,  viz. — all  those  of  the  face  except  the  malar,  and  the 
frontal  and  sphenoid  of  the  cranium.  -  It  is  developed  by  3  centres,  i  for 
each  lateral  mass,  and  i  for  the  body,  ossification  being  completed  about 
the  6th  year.  There  are  no  muscles  attached  to  it. 


THE   MAXILLARY  BONE  27 

OSSA  NASALIA  OR  NASAL  BONES,  (20,  Fig.  8) 

The  Nasal  are  2  small  bones  forming  the  bridge  of  the  nose  by  articula- 
tion with  each  other  in  the  median  line  (4).  From  side  to  side  they  are 
convex  externally  and  concave  internally,  where  they  are  grooved  longi- 
tudinally for  the  external  branch  of  the  naso-ciliary,  or  nasal  nerve  and 
some  small  arteries.  They  are  perforated  about  the 
centre  by  a  foramen  (i),  for  a  small  tributary  to  the 
facial  vein.  The  superior  border  (2)  articulates  with 
the  nasal  notch  of  the  frontal  bone;  the  inferior  bor- 
der (3)  serves  for  the  attachment  of  the  lateral  car- 
tilage of  the  nose.  The  external  border  (5)  articu- 
lates with  the  nasal  process  of  the  maxilla;  the  in- 
ternal border  (4)  with  its  fellow,  with  the  nasal  spine 
of  the  frontal  above  and  with  the  ethmoid  bone  below. 
They  are  each  developed  by  one  centre  of  ossification, 
and  have  no  muscles  attached  to  them  except  a  few 
fibres  of  the  occipito-frontalis. 

THE  MAXILLA,  (18,  Fig.  8) 

The  Maxillae  are  2  hollow  bones,  together  forming  the  upper  jaw. 
Each  bone  consists  of  4  processes,  and  a  body  which  possesses  interiorly 
a  large  cavity,  the  sinus  maxillaris,  or  antrum  of  Highmore. 

Antrum  of  Highmore  ja  a  tetrahedral  oa_yjiy  in  the  body  of  the  bone, 
whichjpj3ens  into  the  middle  meatus  of  the  nose  by  an  aperture  which  is 
very  small  in  the  recent  subject,  admitting  only  a  small  probe.  Its  walls 
are  very  thin,  and  are  covered  internally  by  mucous  membrane.  It  pre- 
sents~the — 

Aperture, — partly  closed  by  the  articulation  of  the  uncinate,  or  unciform 
process  of  the  ethmoid  with  the  ethmoidal  process  of  the  inferior 
turbinal,  and  that  of   the  maxillary  process  of  the  palate  with  a 
fissure  in  the  maxilla;  also  by  the  maxillary  process  of  the  inferior 
turbinal  which  hooks  over  the  lower  edge  of  the  orifice. 
Posterior  Dental  Canals, — on  the  posterior  wall  of  the  cavity. 
Processes, — in  its  floor,  formed  by  the  alveoli  of  the  ist  and  2d  molar 

teeth,  the  roots  of  which  occasionally  perforate  it. 
Other  Points  presented  by  the  body.     The  body  has  4  surfaces,  the 
facial  externally,  the  zygomatic  posteriorly,  the  orbital  superiorly,  and  an 
internal  surface  forming  part  of  the  outer  wall  of  the  nose  and  the  cavity 
of  the  mouth.     The  anterior  or  facial  surface  presents  the — 


28 


HUMAN    ANATOMY 


FIG. 


Incisive  Fossa  (2), — on  the  facial  surface,  above  the  incisor  sockets,  for 

the  origin  of  the  depressor  alae  nasi  muscle. 

Canine  Fossa  (i), — more  externally,  for  the  levator  anguli  oris  muscle. 
Infraorbital  Foramen  (3), — above  the  canine  fossa,  transmitting  the 
infraorbital  vessels  and  nerve,  from  the  infraorbital  canal  in  the  orbital 
surface  of  the  bone. 

Maxillary  Tuberosity  (7), — articulates  with  the  tuberosity  of  the  palate 
bone.  The  nasal  surface  presents — 

Conchal  or  Turbinal  Crests, — inferior 
and  superior,  for  articulation  with 
inferior  and  middle  conchae,  bound- 
ing horizontal  grooves  which  cor- 
respond to  the  meati  of  the  nose. 
Vertical  Grooves, — on  the  inner  sur- 
face, one,  the  lacrimal,  assisting 
to  form  the  nasal  duct,  the  other, 
pterygo-palatine,  to  form  the  ptery- 
go-palatine,  or  posterior  palatine 
canal. 
Rough  Surface, — for  articulation  with 

the  palate  bone. 

Orbital  Surface, — articulating  with 
the  lacrimal,  ethmoid,  and  palate 
bones  interiorly,  partly  bounding 

the  spheno-maxillary  fissure  exteriorly,  and  forming  the  lower  mar- 
gin of  the  orbit  anteriorly. 

Infraorbital  Groove  (n), — along  the  orbital  surface,  ending  in  the  infra- 
orbital  canal  and  foramen.     (See  above.) 
Depression, — for  the  origin  of  the  inferior  oblique  muscle  of  the  eye. 

Processes  of  the  maxilla  are  4  in  number,  as  follows: — 
MALAR  or  ZYGOMATIC  PROCESS  (4,  5), — is  triangular,  looks  outward  from 

the  body,  and  is  rough  for  articulation  with  the  malar  bone. 
NASAL  or  FRONTAL  PROCESS  (8), — is  thin  anteriorly  and  serrated  superiorly 

(12)  for  articulation  with  the  nasal  bone;  posteriorly  it  is  smooth  and 

articulates  with  the  lacrimal.     It  presents  the — 

Conchal  or  Turbinal  Crests, — superior  and  inferior,  the  former  articu- 
lating with  the  middle  concha  or  turbinal  process  of  the  ethmoid 
bone. 

Outer  Surface, — gives  origin  to  the  orbicularis  palpebrarum  and  levator 
labii  superioris  alaeque  nasi  muscles,  and  the  tendo  oculi. 


THE    LACRIMAL  BONE  2Q 

Lacrimal  Groove, — on  the  posterior  border  (9),  helping  to  form  the  nasal 

canal. 
ALVEOLAR  PROCESS  (6), — forms  the  curved  line  of  the  teeth,  and  presents 

— Alevoli, — or  sockets,  for  8  teeth  in  the  adult,  5  in  the  child. 
PALATINE  PROCESS, — forms  part  of  the  floor  of  the  nasal  cavity,  and  the 
roof  of  the  mouth.     It  articulates  with  the  vomer,  the  palate  bone, 
and  with  its  fellow  process,  and  presents  the — 

Incisive  Foramen,  or  Foramen  of  Stenson, — leading  into  the  anterior 
palatine  canal,  for  the  terminal  branches  of  the  posterior  palatine 
arteries. 

Foramina  of  Scar  pa,  2, — transmitting  the  naso-palatine  nerves. 
Groove, — on  the  under  surface,  for  the  protection  of  the  vessels  and 

nerves. 

Orifice, — of  the  posterior  palatine  canal,  at  the  posterior  end. 
Nasal  Crest, — at  the  articulation  of  the  two  processes  with  the  vomer. 
Anterior  Nasal  Spine  (10), — the  anterior  extremity  of  the  nasal  crest. 
Articulations    and    Development.     The    maxilla    articulates    with    9 
bones,— the  frontal  (12),  ethmoid  (14),  vomer  (13),  nasal  (15),  lacrimal, 
malar,  palate,  inferior  turbinal,  and  opposite  maxilla.     It  is  developed 
probably  by  4  centres, — i  for  the  facial  and  nasal  parts,  another  for  the 
orbital  and  malar,  a  3d  for  the  incisive,  and  a  4th  for  the  palate  portion. 

Muscles  attached  to  it,  are  n,  viz. — the  orbicularis  palpebrarum,  and 
levator  anguli  oris  alaeque  nasi,  2,  to  the  nasal  process; — the  levator  labii 
superioris,  levator  anguli  oris,  compressor  naris,  depres- 
sor alae  nasi,  orbicularis  oris,  and  inferior  oblique  of  the 
eye,  6,  to  the  body; — the  buccinator,  i,  to  the  alveolar 
process; — the  masseter,   i,  to  the  malar  process; — and 
the  external  pterygoid,  i,  to  the  tuberosity. 

THE  OSSA  LACRIMALIA  OR  LACRIMAL  BONES 

The  Lacrimal  are  2  small  quadrilateral  bones,  situated 
in  the  anterior  part  of  the  inner  wall  of  the  orbit.  Each 
bone  presents  a — 

Groove  (3), — on  the  external  surface,  forming  part  of  the  nasal  canal. 

Ridge  (i), — also  externally,  for  attachment  of  the  tensor  tarsi  muscle. 

Furrow, — internally,  corresponding  to  the  ridge  on  the  external  surface. 

Hamular  Process  (2), — projecting  forwards  around  the  nasaj  canal. 

Superior  Border  (8),— articulates  with  the  internal  angular  process  of 
the  frontal  bone. 


30  HUMAN    ANATOMY 

Inferior  Border  (9), — articulates  anteriorly  with  the  lacrimal  process 
of  the  inferior  turbinal  bone. 

Anterior  Border  (6), — articulates  with  the  nasal  process  of  the  maxilla. 

Posterior  Border  (7), — articulates  with  the  orbital  plate  of  the  ethmoid 
bone. 

Internal  Surface, — closes  the  anterior  ethmoidal  cells. 

Articulations,  Development,  and  Muscles.  The  lacrimal  articu- 
lates with  4  bones, — the  frontal,  ethmoid,  maxilla,  and  inferior  turbinal. 
It  is  developed  from  i  centre,  and  has  but  i  muscle  attached  to  it,  the  tensor 
tarsi  or  Homer's  muscle. 

THE  OSSA  ZYGOMATICA,  OR  MALAR  BONES,   (14,   Fig.   8) 

The  Malar  or  cheek  bones  are  situated  at  the  outer  and  upper  part  of  the 
face,  aiding  to  form  the  cavities  of  the  orbits  and  the  temporal  and 
zygomatic  fossae.  Each  bone  presents  3  surfaces,  3  processes  and  3 
borders. 

The  Orbital  surface  (c)  forming  the  lateral  and  front  part  of  the  orbit, 
is  concave  laterally;  it  is  bounded  in  front  by  the  margin  of  the  orbit  (6) 
and  behind  by  the  rough  orbital  border.     About  the 
FIG.  1 8.         middle  of  this  surface  is  seen  the  orbital  ends  of  the 
Zygomatico-facial,  or  malar,  canals.     The  Zygomatic, 
or  infratemporal  surface  forms  the  front  end  of  the 
zygomatic  arch.     The  facial  surface  is  subcutaneous  and 
is  also  known  as  the  malar  surface  or  malar  tuberosity; 
it   presents    the   outer   ends  of  the  two   small    malar 
canals.     Orbital,    or   fronto-sphenoidal    process    (a)    in 
man,  and  those  animals  having  a  closed  orbit,  articu- 
lates with  the  great  wing  of  the  sphenoid  and  the  orbital  process  of  the 
frontal  bone.     It  forms  the  upper  end  of  the  temporal  border  (h)  which 
forms  the  anterior  boundary  of  the  temporal  fossa  and  is  continuous  with 
the   temporal   ridge  of   the  skull.    This  border  terminates   below  and 
behind  in  the  zygomatic  or  temporal  process  (/),  which  is  rough  for  ar- 
ticulation with  the  zygomatic  process  of  the  temporal  bone.     The  lower 
or  masseteric  border  (g)  is  rough  for  attachment  of  the  masseter  and 
zygomatic  muscles.     It  terminates  medially  in  the  long  slender  maxillary 
process  (d)  which  is  very  rough  for  articulation  with  the  maxilla  and 
forms  most  of  the  lower  margin  of  the  orbit  (&). 

Articulations,  Development,  and  Muscles.  The  malar  articulates 
with  4  bones, — the  frontal,  sphenoid,  temporal,  and  maxilla.  It  is 


THE   PALATE   BONES  3! 

developed  by  one  centre  of  ossification,  and  has  4  muscles  attached  to 
it, — the  levator  labii  superioris,  zygomaticus  major  and  minor,  and  the 
masseter. 

THE  PALATE  BONES 

The  Palate  Bones  are  2  L-shaped  bones,  situated  posteriorly  in  the 
nares.  Each  bone  assists  in  forming  the  floor  and  outer  wall  of  the 
nose,  the  roof  of  the  mouth,  the  floor  of  the  orbit,  the  inner  wall  of  the  an- 
trum,  the  zygomatic,  spheno-palatine,  and  pterygoid  fossae,  and  presents 
the  following  points : — 

HORIZONTAL  PLATE  (a),  completes  the  nasal  floor  and  hard  palate;  has  a — 
Ridge, — on  the  inferior  surface,  for  the  tensor  palati  aponeurosis. 
Groove, — assisting  to  form  the  posterior  palatine  canal. 
Foramina, — transmitting  the  anterior  and  posterior 

palatine  nerves. 
Anterior  Border, — is  serrated,  for  articulation  with 

the  maxilla. 

Posterior  Border, — is  free  and  concave,  for  the  at- 
tachment of  the  soft  palate. 

Inner  Border  (d), — is  thick,  and  articulates   with 

its  fellow,  forming  a  groove  for  the  reception 

of  the  vomer.     Its  posterior  extremity  is  the — 

Posterior  Nasal  Spine, — for  the  origin  of  the  azygo 

uvulae  muscle. 
VERTICAL  PLATE  (6),  a  broad  and  thick  lamella,  pre- 
sents the  following: — 

Ridge  for  Middle  Concha, — on  the  inner  surface.     Below  it  is  the — 
Ridge  for  Inferior  Concha  (g), — dividing  the  middle  meatus  of  the  nose 
from  the  inferior,  and  articulating  with  the  inferior  concha  or  turbinal 
bone. 

Posterior  Border, — articulates  with  the  pterygoid  process  of  the  sphenoid. 
Groove, — on  the  external  surface,  helping  to  form  the  posterior  palatine, 

or  pterygo-palatine  canal. 

Two  Smooth  S urfaces  —  externally,  one  forming  the  inner  wall   of   the 
spheno-palatine  or  pterygo-palatine  fossa;  the  other,  part  of  the  inner 
wall  of  the  maxillary  antrum. 
Two   Rough    Surfaces— also   externally,   one   for  articulation   with   the 

maxilla;  the  other  with  the  pterygoid  process  of  the  sphenoid. 
Deep  Notch, — which  by  articulation  with  the  sphenoid  bone,  forms  the 
spheno-palatine  foramen  (A),— for  the  spheno-palatine  vessels  and  the 
superior  nasal  and  palatine  nerves. 


32  HUMAN    ANATOMY 

TUBEROSITY  OR  PYRAMIDAL  PROCESS  (c),  is  wedged  into  the  notch  between 

the  plates  of  the  pterygoid  process  of   the  sphenoid,   with   which   it 

articulates  laterally.     In  it  are  the — 

Palatine  Foramina, — for  the  anterior,  middle  and  posterior  palatine 
nerves. 

Posterior  Surface, — aids  in  forming  the  pterygoid  fossa. 
ORBITAL  PROCESS  (*), — triangular  in  shape,  large  and  hollow.     It  has — 

Three  Articular  Surfaces, — for  the  maxiJla,  sphenoid,  and  ethmoid. 

Two  Free  Surfaces, — the  orbital  forming,  part  of  the  floor  of  the  orbit,  the 
external  aiding  to  form  the  spheno-palatine  fossa. 

Rounded  Border, — forms  a  part  of  the  spheno-maxillary  fissure. 
SPHENOIDAL  PROCESS  (j),  projects  backward,  articulates  superiorly  with 

the  body  of  the  sphenoid,  and  externally  with  the  pterygoid  process  of 

the  sphenoid.     On  its  upper  surface  is  a — 

Groove, — which  assists  in  forming  the  spheno-palatine  or  pharyngeal 
canal. 

Inner  Surface, — forms  part  of  the  outer  wall  of  the  nasal  fossa. 

Articulations,  Development,  and  Muscles.  The  palate  articulates 
with  6  bones, — the  sphenoid,  ethmoid,  vomer,  maxilla,  inferior  turbinal, 
and  its  fellow  palate  bone.  It  is  developed  by  one  centre  at  the  junction 
of  the  two  plates.  There  are  4  muscles  attached  to  it, — the  azygos  uvulae, 
internal  pterygoid,  superior  constrictor  and  tensor  palati. 

THE  CONCH^E  NASALES  INFERIORES  OR  THE  INFERIOR 
TURBINAL  BONES 

The  Inferior  Turbinal  Bones  are  2  thin,  curved  osseous  plates  situated  in 
the  nasal  fossae,  their  convex  surfaces  presenting  inwardly.     Each  bone  is 
pIG.  20.  attached  above  to  the  inferior  turbinal  crests 

of  the  maxillary  and  palate  bones,  and  presents 
the  following,  viz. — 

Lacrimal  Process  (3), — aiding  to  form  the 
nasal  duct,  by  articulation  with  the  lacri- 
mal  and  maxilla. 

Ethmoidal  Process  (i), — articulating  with  the  unciform  process  of  the 
ethmoid,  thus  helping  to  partially  close  the  aperture  of  the  antrum. 
Maxillary  Process  (4), — also  helps  to  partially  close  the  aperture  of  the 

maxillary  antrum,  by  hooking  (7)  over  the  lower  edge  of  that  orifice. 
Free  Border  (5), — below,  coming  to  about  %  inch  above  the  floor  of  the 
nose. 


THE  VOMER    AND   MANDIBLE  33 

Articulations,  Development  and  Muscles.  The  inferior  turbinal  ar- 
ticulates with  4  bones,  the  ethmoid,  lacrimal,  palate,  and  maxilla.  It 
is  developed  by  one  centre,  and  has  no  muscles  attached  to  it. 

THE  VOMER 

The  Vomer  (plough-share)  forms  the  postero-inferior  part  of  the  nasal 
septum,  but  is  usually  bent  to  one  side.  Its — 

Superior  Border  (i,  2), — has  a  groove  and  two  alae  or  wings,  for  articula- 
tion with  the  rostrum  and  vaginal  proc- 
esses of  the  sphenoid  bone. 
Anterior   Border    (3), — is   grooved    for    the 

ethmoidal  plate  and  the  jiasal  cartilage. 
Inferior  Border  (4), — the  longest,  articulates 
with  the  nasal  crest  of  the  maxillary  and 
palate  bones. 

Posterior  Border, — is  free  and  presents  toward  the  pharynx. 
Naso-palatine  Grooves, — laterally,  for  the  naso-palatine  nerves. 
Furrows, — on  the  lateral  surfaces  (6),  for  vessels  and  nerve-filaments. 
Articulations,    Development    and    Muscles.     The    vomer    articulates 
with  6  bones, — the  sphenoid,  ethmoid,  2  maxillary,  and  2  palate  bones. 
It  is  developed  by  one  centre,  which  appears  about  the  6th  foetal  week  in 
cartilage  between  two  laminie  which  coalesce  after  puberty.     It  has  no 
muscles  attached  to  it. 


THE  MANDIBLE,  (25,  Fig.  8) 

General  Characteristics.  The  Mandible  is  the  lower  jaw,  receives  the 
inferior  teeth,  and  is  the  second  bone  of  the  body  in  which  ossification 
appears,  the  clavicle  being  the  first.  It  consists  of  a  body  and  two  rami. 

The  Body  (i)  is  shaped  somewhat  like  a  horseshoe,  and  presents  for 
examination  the  following: — 

Alveolar  Portion  (15), — above  the  oblique  line,  containing  on  its  upper 
border  alveoli  for  16  teeth  in  the  adult,  for  10  in  the  child  (i,  b,  c,  m). 
Symphysis  (3), — a  vertical  ridge  on  the  median  line,  marking  the  junc- 
tion of  the  two  symmetrical  portions  of  which  the  bone  originally 
consisted. 
Mental  Process, — a  prominent  triangular  eminence,  characteristic  of 

man,  forming  the  chin. 

Externally  on  each  side  from  the  symphysis  backward,  are  the — 
3 


34  HUMAN   ANATOMY 

Incisive  Fossa  (4), — above  the  chin,  for  the  origin  of  the  levator  menti. 
Meatal  Foramen  (5), — below  the  2d  bicuspid  alveolus,  transmitting  the 

mental  artery  and  nerve. 

External  Oblique  Line  (i), — for  the  origins  of  the  depressor  labii  infe- 
pIG    22  rioris  and    depressor  anguli 

oris  muscles  from  its  anterior 
half. 
Groove  (7), — near    the     angle, 

for  the  facial  artery. 
Internally,  on  each  side  from  the 
median   depression   backward, 
are  the— 

Mental  Spines,  or  Genial  Tuber- 
cles,— the    superior    for    the 
genio-hyoglossus  muscle;  the 
inferior  for  the  genio-hyoid. 
Mylo-hyoid  Ridge, — obliquely  backward,  for  the  mylo-hyoid  muscle. 
Sublingual  Fossa, — near  the  genial  tubercles,  for  the  sublingual  gland. 
Fossa, — below  the  sublingual,  for  the  anterior  belly  of  the  digastric 

muscle. 
Submandibular  Fossa, — below  the  ridge,  for  the  submandibular  gland. 

The  Rami  of  the  Mandible,  the  ascending  portions  of  the  bone,  are  2 
in  number,  and  each  presents  the — 

Coronoid  Process  (10), — anteriorly,  for  the  insertion  of  the  temporal 

muscle. 
Condylar  Process  (n), — posteriorly.     Its  condyle  articulates  with  the 

glenoid  fossa  of  the  temporal  bone,  its  neck  receives  the  insertion  of  the 

external  pterygoid  muscle,  its  tubercle  has  attached  to  it  the  external 

lateral  ligament  of  the  lower  jaw. 
Sigmoid  Notch  (12), — a  deep  depression  separating  the  above-named 

processes  from  each  other,  and  crossed  by  the  masseteric  vessels 

and  nerve. 
Groove, — on  the  coronoid  process  internally,  and  prolonged  downward 

upon  the  body,  for  the  attachment  of  the  buccinator  muscle. 
Ridges, — on  the  external  surface,  for  the  insertion  of  the  masseter. 
Lingula  or  Spix's  Spine, — a  projection  on  the  margin  of  mandibular 

foramen,  for  the  attachment  of  the  spheno-mandibular  ligament. 
Mandibular  Foramen,  or  Canal  (13), — opening  behind  the  spine,  lies 

within  the  ramus  and  body  of  the  bone  for  the  inferior  dental  vessels 

and   nerve.     It   communicates   with   each   alveolus   and   with   the 

mental  foramen. 


THE    ORBITS  35 

Mylo-hyoid  Groove  (14), — below  the  spine,  for  the  mylo-hyoid  vessels  and 

nerve. 

Rough  Surface, — behind  the  groove,  for  the  internal  pterygoid  muscle. 
Angle  of  the  Jaw  (8), — at  the  junction  of  the  posterior  border  of  the 

ramus  with  the  inferior  border  of  the  body,  for  the  insertion  of  the 

masseter  and  internal  pterygoid  muscles,  and  the  stylo-mandibular 

ligament. 

Articulations  and  Development.  It  articulates  with  one  pair  of  bones, 
— the  temporal.  It  is  the  earliest  formed  bone  in  the  body  except  the 
clavicle,  and  is  probably  developed  by  2  centres,  one  for  each  lateral  half, 
the  two  halves  coalescing  at  the  symphysis  about  the  ist  year  of  age. 
In  adult  life  the  ramus  arises  almost  vertically  from  the  body,  and  the 
dental  canal  lies  about  the  middle  of  the  body.  In  old  age  the  ramus 
seems  to  extend  obliquely  backward,  the  angle  becoming  very  obtuse; 
and  the  alveolar  portion  being  absorbed,  the  dental  canal  is  near  the 
superior  border. 

Muscles  attached  to  the  Mandible, — number  15  pairs, — the  masseter, 
internal  and  external  pterygoids  and  temporal,  4,  to  the  ramus; — the 
genio-hyo-glossus,  genio-hyoid,  mylo-hyoid,  digastric,  and  superior  con- 
strictor, 5,  to  the  internal  surface  of  the  body; — the  depressor  labii  inferioris, 
depressor  anguli  oris,  levator  menti,  orbicularis  oris,  platysma  myoides, 
and  buccinator,  6,  to  the  external  surface  of  the  body. 

'M  T-E  ORBITS 

The  Orbits  are  2  conoidal  cavities,  situated  between  the  forehead  and 
the  face,  their  bases  outward,  their  apices  pointing  backward,  the  lines  of 
axial  prolongation  meeting  at  the  sella  turcica  of  the  sphenoid  bone.  They 
contain  the  organs  of  vision  with  their  appendages,  and  are  each  formed 
by  7  bones, — the  frontal  (i),  ethmoid  (2),  sphenoid  (3,  4,  5),  lacrimal 
(6),  maxilla  (7),  palate  (8),  and  malar  (9),  of  which  the  first  three  are  com- 
mon to  both  orbits.  Each  orbit  communicates  with  i  cavity  and  4  fossae, 
as  follows,  viz. — • 

Cavity  of  the  cranium, — by  the  optic  foramen  (u)  and  superior  orbital 

or  sphenoidal  fissure  (10). 

Fossa  (4), — the  nasal,  temporal,  zygomatic,  and  spheno-palatine  or 
spheno-maxillary, — by  the  nasal  duct  (12)  and  the  inferior  orbital  or 
spheno-maxillary  fissure  (13). 

Foramina  communicating  with  each  orbit  are  9  in  number, — the  optic 
foramen  (u),  superior  orbital  or  sphenoidal  fissure  (10),  anterior  (21)  and 


36 


HUMAN    ANATOMY 


FIG.  23. 


posterior  (22)  ethmoidal  foramina,  supraorbital  (14),  infraorbital  (15), 
and  zygomatico-facial  and  temporal  or  malar  foramina  (16),  the  nasal 
or  lacrimal  canal  (12),  and  the  inferior  orbital  or  spheno-maxillary 
fissure  (13). 

Roof  of  the  Orbit  is  formed  by  the  orbital  plate  of  the  frontal  bone  ante- 
riorly (i),  and  the  lesser  wing  of  the  sphenoid  (4)  posteriorly.  It  is  con- 
cave, and  presents  the — 

Lacrimal  Fossa  (17), — at  its  outer  angle,  for  the  lacrimal  gland. 

Fovea  Trochlearis  (18), — at  the 
inner  angle,  for  the  pulley 
of  the  superior  oblique. 
Floor  of  the  Orbit  is  formed 
by   the   orbital    surface    of   the 
maxilla    (7),    and    the    orbital 
process  of  the  malar  (9)  and  pal- 
ate bones  (8). 

It  is  nearly  flat  and  presents  the— 
Palato-maxillary  Suture, — pos- 
teriorly. 

Infraorbital  Canal,— anteriorly. 
Infraorbital  Groove  (9), — pos- 
teriorly. 

Medial  or  Inner  Wall  of  the 
Orbit  is  formed  by  the  nasal 
process  of  the  maxilla  (20),  the 

lacrimal  (6),  the  orbital  plate  or  lamina  papyracea  of  the  ethmoid  (2), 
and  the  body  of  the  sphenoid  (3).  It  presents — 

A  Groove, — for  the  lacrimal  sac,  and  the  Lacrimal  Crest,  anteriorly. 
2  Sutures, — the  ethmo-lacrimal,  and  the  ethmo-sphenoidal. 

Lateral  or  Outer  Wall  of  the  Orbit  is  formed  by  the  orbital  process  of  the 
malar  bone  (9),  and  the  greater  wing  of  the  sphenoid  (5).  It  presents  the 
Orifices  (16)  of  the  zygomatico-facial  and  zygomatico- temporal  or  malar 
canals,  and  the  Spheno-malar  Suture. 

Angles  of  the  Orbit  present  the  following  points: — 

IN  THE  SUPERIOR  EXTERNAL  ANGLE: 

Superior  Orbital  or  Sphenoidal  Fissure  (10),  or  Foramen  Lacerum 
Anterius, — transmits  the  3d,  4th,  ophthalmic  division  of  the  5th, 
and  the  6th  nerves,  the  ophthalmic  vein,  branches  of  the  lacrimal 


THE  FOSS.E  OF  THE  SKULL  37 

and  middle  meningeal  arteries,  filaments  of  the  sympathetic  nerve, 
and  a  process  of  the  dura  mater. 
Articulations, — the  fronto-malar,  and  fronto-sphenoidal. 

IN  THE  SUPERIOR  INTERNAL  ANGLE: — 

Suture, — the  lachrymo-ethmo-frontal,  in  which  are  the  following  fora- 
mina: 

Anterior  Ethmoidal  Foramen  (21), — transmitting  the  anterior  ethmoidal 
artery  and  the  nasal  nerve. 

Posterior  Ethmoidal  For  amen  (22), — transmitting  the  posterior  ethmoidal 
artery  and  vein. 

IN  THE  INFERIOR  EXTERNAL  ANGLE: 

Inferior  Orbital  or  Spheno-maxittary  Fissure  (13) — (described  under  the 
Zygomatic  Fossa). 

IN  THE  INFERIOR  INTERNAL  ANGLE: — 

A  Suture, — the  ethmo-maxillo-palato-lacrimal. 

Other  Points  connected  with  the  Orbit  are  two,  the  supraorbital  notch 
and  the  optic  foramen,  as  follows: — 

Supraorbital  Notch  or  Foramen  (14), — at  the  junction  of  the  inner  and 
middle  thirds  of  the  upper  circumference,  transmitting  the  supra- 
orbital  artery,  veins,  and  nerve.  A  line  prolonged  from  this  notch 
through  the  interval  between  the  bicuspid  teeth  of  either  jaw,  will 
cross  both  the  infraorbital  and  mental  foramina,  and  the  canine  fossa 
of  the  maxilla. 

Optic  Foramen  (n), — at  the  apex,  is  formed  by  the  2  roots  of  the  lesser 
wing  of  the  sphenoid,  and  transmits  the  optic  nerve  and  the  ophthal- 
mic artery.  From  around  its  margin  arises  a  tendinous  ring,  the 
common  origin  of  the  4  recti  muscles  of  the  eye. 

Muscles  arising  within  the  Orbit  are  the  4  recti  and  2  oblique  of  the  eye, 
the  levator  palpebrae,  and  the  tensor  tarsi  (8  in  all). 

THE  FOSSJE 

The  Nasal  Fossae  together  form  the  cavity  of  the  nose,  being  separated 
from  each  other  by  the  Septum  Nasi  (n).  They  open  in  front  by  the 
anterior  nares,  behind  by  the  posterior  nares;  and  extend  from  the  palate 
processes  of  the  maxilla  and  palate  bones  (17),  upward  to  the  base  of  the 
cranium.  They  are  formed  by  14  bones, — the  ethmoid,  sphenoid, 
frontal,  vomer,  2  nasal,  2  maxillae,  2  lacrimal,  2  palate  and  2  inferior  con- 
chae  or  turbinal. 

The  Septum  Nasi  (n)  forms  the  inner  wall  of  each  nasal  fossa,  and  is 
formed  chiefly  by  the  perpendicular  plate  of  the  ethmoid  bone,  the  vomer. 


38  HUMAN   ANATOMY 

and  the  triangular  cartilage  of  the  septum;  to  a  less  extent  by  5  other  bones, 
— the  rostrum  of  the  sphenoid,  the  nasal  spine  of  the  frontal,  and  the  crests 
of  the  nasal,  palate,  and  maxillary  bones. 

Points  presented  by  each  Nasal  Fossa  are  as  follows: — 
ON  THE  ROOF  : — 

Openings, — posteriorly,  into  the  sphenoidal  sinuses. 

Olfactory  Foramina, — and  the  Nasal  Slit,  -in  the  cribriform  plate  of  the 

ethmoid  bone. 
ON  THE  FLOOR: — 

Orifice, — of  the  anterior  palatine  canal. 

Suture, — between  the  bones  forming  the  hard  palate. 

Nasal  Spine, — anterior  and  posterior,  and  the  Ridge  connecting  them. 

ON  THE  LATERAL  OR  OUTER  WALL, 

FIG.  24.  from  above  downward: — 

Superior    Concha    or   Turbinal 

Process, — of  the  ethmoid. 
Superior  Meatus  of  the  nose — 
into  which  open  3  orifices, — 
those  of  the  posterior  eth- 
moidal  and  the  sphenoidal 
sinuses,  and  the  sphenopala- 
tine  foramen. 

Middle    Concha     or     Turbinal 
Process  (7), — of  the  ethmoid. 
Middle  Meatus  of  the  nose, — • 
into  which  open   2   orifices, 
those  of  the  antrum  (14)  and 

infundibulum,  the  latter  draining  the  anterior  ethmoidal  cells  (8), 
and  the  frontal  sinus. 

Inferior  Concha  or  Turbinal  Bone  (10), — below  which  is  the — 
Inferior  Meatus — of  the  nose,  the  largest;  into  it  open  2  orifices,  those 
of  the  lacrimal  and  anterior  palatine  canals.     To    these    may   be 
added  the  apertura  pyraformis  (anterior)  and  posterior  nares. 

The  Temporal  Fossa.  Situated  on  each  side  of  the  cranium,  it  is  shallow 
above  and  behind,  but  deep  in  front  and  below,  and  is  formed  by  parts 
of  5  bones, — the  frontal,  sphenoid,  temporal,  parietal,  and  malar.  It  is 
bounded  above  and  behind  by  the  temporal  ridge,  in  front  by  the  malar, 
frontal,  and  sphenoid  bones,  and  below  by  the  zygoma  and  the  pterygoid 
bounded  above  and  behind  by  the  temporal  ridge,  in  front  by  the  malar, 
frontal,  and  sphenoid  bones,  and  below  by  the  zygoma  and  the  pterygoid 


SUTURES    AND   FONTANELLES  39 

ridge  on  the  greater  wing  of  the  sphenoid.  It  is  traversed  by  6  sutures, — 
the  spheno-malar,  spheno-frontal,  spheno-parietal,  spheno-temporal, 
frontal-parietal,  and  temporo-parietal.  It  opens  below  into  the  zygomatic 
fossa;  and  lodges  the  temporal  muscle,  and  the  deep  temporal  vessels. 

The  Zygomatic  Fossa  extends  downward  from  the  temporal  fossa,  and 
is  bounded — 

In  front, — by  the  tuberosity  of  the  maxilla. 

Laterally  or  Externally, — by  the  zygoma,  and  the  ramus  of  the  mandible. 

Medially  or  Internally, — by  the  lateral  or  external  plate  of  the  pterygoid 

process. 
Above, — by  the  temporal  fossa,  the  squamous  portion  of  the  temporal 

bone  and  the  greater  wing  of  the  sphenoid. 
Below, — by  the  alveolar  border  of  the  mandible  bone. 

Fissures  opening  into  the  Zygomatic  Fossa  are  two,  the — 
Inferior  Orbital  or  Spheno-maxillary  Fissure, — between  the  greater  wing 
of  the  sphenoid  externally,  and  the  maxilla  and  palate  bones  medially 
or  internally.  It  connects  the  orbit  with  the  zygomatic,  temporal,  and 
spheno-palatine  fossse;  and  transmits  the  infraorbital  artery,  the  maxil- 
lary nerve  and  its  orbital  branches,  and  the  ascending  branches  of 
Meckel's  ganglion. 

Pterygo-maxillary  Fissure, — between  the  tuberosity  of  the  maxilla  and 
the  pterygoid  process  of  the  sphenoid.  It  transmits  branches  of 
the  internal  maxillary  artery,  and  connects  the  zygomatic  fossa  with 
the  spheno-palatine. 

The  Spheno-palatine  Fossa  is  a  triangular  cavity  between  the  pterygoid 
process  of  the  sphenoid  bone  and  the  tuberosity  of  the  maxilla,  and  is 
situated  at  the  junction  of  the  spheno-maxillary,  pterygo-maxillary,  and 
sphenoidal  fissures.  Into  it  open — 

3  FOSSCE, — the  orbital,  zygomatic,  and  nasal. 
2  Cavities, — the  cranial,  and  buccal. 

5  Foramina, — the  Vidian  and  spheno-palatine  or  pharyngeal  canals  and 
the  foramen  rotundum,  posteriorly;  the  spheno-palatine  foramen  on 
the  inner  wall;  and  the  posterior  palatine  canal  interiorly,  occasion- 
ally also  the  accessory  palatine  canals. 

THE  SUTURES  AND  FONTANELLES 

The  Sutures  of  the  Skull  are  13  in  number,  as  follows: — 
At  the  vertex  of  the  skull  are  3,  the — 


40  HUMAN   ANATOMY 

Sagittal  or  Interparietal, — formed  by  the  junction  of  the  two  parietal 

bones. 
Metopic,  between  the  halves  of  the  Frontal,  may  persist  until  late  in 

life. 
Coronal  or   Fronto-parietal, — extends   transversely  across   the  vertex 

of  the  skull  anteriorly. 
Lambdoid  or  Occipito-parietal, — extends  transversely  across  the  vertex 

of  the  skull  posteriorly. 
At  the  sides  of  the  skull  are  5,  the — 

Fronto-malar  and  Fronto-sphenoidal, — anteriorly. 
Spheno- parietal,  Squamo- parietal  and  Masto- parietal, — posteriorly. 
At  the  base  of  the  skull  are  5,  the — • 

Basilar, — in  the  central  line  of  the  base. 

Petro-occipital,  Masto-occipital,  Petro-sphenoidal  and  Squamo- sphenoidal 

— on  each  side. 

The  Facial  Sutures  are  very  numerous,  the  most  important  being  the 
following: — 

Zygomatic  Suture, — at  the  temporo-malar  articulation. 

Transverse  Suture, — extending  from  one  external  angular  process  of 
the  frontal  bone  across  to  the  other,  and  connecting  that  bone  with 
the  malar,  sphenoid,  ethmoid,  lacrimal,  maxillary,  and  nasal  bones. 

Symphysis  of  the  Chin, — the  site  of  a  fcetal  suture. 

The  Sutures  are  formed  by  dentations  of  the  external  tables  inter- 
digitating  with  each  other,  the  adjacent  edges  of  the  internal  tables  lying 
in  unjoined  proximity.  The  sutures  are  not  formed  until  a  long  time 
after  the  formation  of  the  skull,  probably  to  permit  of  the  marginal  growth 
of  the  bones. 

The  Fontanelles  are  6  membranous  intervals  in  the  infant's  skull, 
corresponding  in  situation  with  the  angles  of  the  two  parietal  bones. 
They  are  as  follows: — 

Anterior, — at  the  junction  of  the  sagittal  and  coronal  intervals. 

Posterior, — at  the  junction  of  the  sagittal  and  lambdoid  intervals. 

Lateral  Fontanelles,  4, — two  at  the  anterior  inferior  angles,  and  two  at 
the  posterior  inferior  angles  of  the  parietal  bones. 

The  Ossa  Suturarum  (Wormian  Bones)  are  supernumerary  small  pieces 
of  bone,  irregularly  shaped,  and  developed  by  special  centres  in  unclosed 
portions  of  the  cranial  sutures  and  fontanelles,  being  most  frequent  in  the 
lambdoid  suture. 


FORAMINA   AT  BASE    OF    SKULL  4! 

The  Hyoid  Bone  is  shaped  like  a  horse-shoe  and  has  no  articulation  with 
the  skeleton,  but  supports  the  tongue.  It  consists  of  a  Body,  two  greater 
and  two  lesser  Cornua  or  horns.  On  the  body  is  a  Crucial  Ridge,  with  a 
Tubercle  at  the  centre.  It  is  developed  by  5  centres, — one  for  the  body 
and  one  for  each  horn.  Attached  to  it  are  10  muscles,  3  ligaments  and  i 
membrane,  as  follows: — 

To  the  Body  or  Basi-hyal, — the  genio-,  mylo-,  stylo-,  sterno-,  thyro-, 
omo-hyoid,  the  genio-hyo-glossus,  and  the  hyo-glossus  muscles;  also 
the  pulley  of  the  digastric,  the  hyo-epiglottic  ligament,  and  the  thyro- 
hyoid  membrane. 

To  the  Greater  Cornu,  or  thyro-hyal, — the  hyo-glossus,  middle  constrictor 
muscles,  and  part  of  the  thyro-hyoid;  also  the  thyro-hyoid  ligament. 
To  the  Lesser  Cornu,  or  cerato-hyal, — the  stylo-hyoid  ligament. 

FORAMINA  AT  THE  BASE  OF  THE  SKULL 

with  the  various  structures  transmitted  by  each  foramen 

Internally,  the  Anterior  Fossa  has  i  single  and  4  pairs,  viz. — 

,    Foramen  Cacum, — lodges  a  fold  of  dura  mater,  and  transmits  a  vein  to 

the  longitudinal  sinus. 

Ethmoidal  Fissure, — the  nasal  branch  of  the  5th  nerve. 
Olfactory, — olfactory   nerves,    and   nasal   branches   of   the   ethmoidal 

arteries. 
Anterior  Ethmoidal, — ant.  ethmoidal  artery  and  the  nasal  br.  of  the  5th 

nerve. 
Posterior  Ethmoidal, — posterior  ethmoidal  artery  and  vein. 

Middle  Fossae  contain  10  foramina  in  each  fossa,  viz. — 
/     Optic  Foramen, — optic  nerve  and  ophthalmic  artery. 
rj    Foramen  Lacerum  Anterius,  Superior  Orbital  or  Sphenoidal Fissure, — the 
3d,  4th,  ophthalmic  division  of  the  5th,  and  the  6th  cranial  nerves  and 
filaments  of  the  sympathetic;   ophthalmic  vein,   a  branch  of  the 
lacrimal  artery,  orbital  branches  of  the  middle  meningeal  artery, 
and  a  process  of  dura  mater. 

Foramen  Rotundum, — maxillary  division  of  the  5th  nerve. 
foramen  Vesalii, — a  small  vein.     This  foramen  is  often  absent. 
Foramen  Ovale, — mandibular  division  of  the  5th  nerve,  lesser  petrosal 
nerve,  and  the  small  meningeal  branch  of  the  internal  maxillary  artery. 
Foramen  Spinosum, — middle  meningeal  artery,  meningeal  veins,  and 

sympathetic  filaments  from  the  cavernous  plexus. 
Foramen  Lacerum  Medium,  is  not  a  true  foramen  in  that  it  is  completely 


42  HUMAN    ANATOMY 

blocked  by  fibro-cartilage,  the  cerebral  surface  of  this  cartilage  is 
deeply  grooved  or  may  even  be  tunneled  from  behind  forwards 
by — internal  carotid  artery,  carotid  plexus,  Vidian  nerve,  and  artery. 

Small  Foramina, — for  the  small  and  external  superf.  petrosal  nerves. 

Hiatus  Canalisfacialis  Fallopil, — large  petrosal  nerve,  and  a  branch  of 
middle  meningeal  artery. 

Posterior  Fossa  contains  6  pairs  and  i  single  foramen,  viz. — 

Meatus  Acusticus  or  Auditor  ins  Intermts, — facial  and  auditory  nerves, 
auditory  artery. 

Aqu&ductus  Vestibuli, — small  artery  and  vein,  process  of  dura  mater. 

Foramen  Lacerum  Posterius  (Jugular  Foramen) , — the  glosso-phary ngeal, 
pneumo-gastric,  and  spinal  accessory  nerves,  internal  jugular  vein, 
meningeal  branches  of  the  ascending  pharyngeal  and  occipital 
arteries. 

;  Mastoid  Foramen  (often  absent), — a  small  vein,  also  occasionally  the 
mastoid  artery. 

Anterior  Condylar  or  Hypoglossal  Foramen, — hypoglossal  nerve,  menin- 
geal branch  from  the  ascending  pharyngeal  artery. 

Posterior  Condylar  Foramen  (often  absent), — posterior  condylar  vein. 

Foramen  Magnum,  medulla  oblongata  and  its  membranes,  the  vertebral 
arteries,  and  the  spinal  accessory  (n.  accessorius)  nerves. 

Externally,  at  the  base  of  the  skull,  from  the  front  backward,  are  22  fora- 
mina on  each  side,  and  i  single,  the  foramen  magnum,  as  follows: — 

Foramina  of  Scar  pa  (2)  (Anterior  Palatine),  2  in  the  median  line, — for 
the  naso-palatine  nerves. 

Foramina  of  Stenson  (2)  (Incisive},  laterally, — terminal  branches  of  the 
posterior  palatine  arteries. 

Posterior  Palatine  (3), — posterior  palatine  vessels,  anterior  palatine 
nerve. 

Accessory  Palatine  Foramina  (i  or  2  on  each  side), — the  middle  and  pos- 
terior (small)  palatine  nerves. 

Orifice  of  the  Posterior  Naris, — air  to  the  lungs. 

Ptery go- palatine  Foramen, — pterygo-palatine  vessels. 

Foramen  Ovale  (10), — mandibular  nerve. 

Orifice  of  the  Vidian  or  Pierygoid  Canal, — the  Vidian  nerve  and  vessels. 

Foramen  Spinosum  (n), — middle  meningeal  artery. 

Foramen  Lacerum  Medium  (12), — see  under  Middle  Fossae. 

Opening  for  the  Eustachian  Tube.— SLIT  to  the  middle  ear. 

Opening  of  Tensor  Tympani  Canal, — the  tensor  tympani  muscle. 


TKE   BASILAR    SURFACE    OF    SKULL 


43 


Glaserian  Fissure, — laxator  tympani  muscle,  tympanic  artery;  lodges  the 

processus  gracilis  of  the  malleus. 
Carotid  Foramen  (19), — internal  carotid  artery,  nerves  from  the  superior 

cervical  ganglion  to  the  carotid  plexus. 

Anterior  Condylar  or  Hypoglossal  Foramen, — Hypoglossal  nerve. 
Foramen  Lacerum  Poster  ins  (20), — see  under  Posterior  Fossa. 

PIG.  25. 


Foramen  for  Jacobson's  Nerve, — tympanic  branch  of  the  glosso-pharyn- 

geal. 

Foramen  for  Arnold's  Nerve, — auricular  branch  of  the  pneumogastric. 
Opening  of  the  Aquaduclus  Cochlea, — artery  and  vein  to  the  cochlea. 
Stylo-mastoid  Foramen  (18), — facial  nerve,  stylo-mastoid  artery. 
Auricular  Fissure, — exit  of  Arnold's  nerve,  auricular  branch  of  the 

vagus. 


44  HUMAN    ANATOMY 

Posterior  Condylar  Foramen, — see  under  Posterior  Fossa. 
Foramen  Magnum  (23), — see  under  Posterior  Fossa. 

Face  presents  4  pairs,  viz. — 

Supraorbital  Foramen  or  Notch, — supraorbital  artery,  vein,  and  nerve. 
Infraorbital  Foramen, — inf raorbital  artery,  vein  and  nerve. 
Orifice  of  the  Anterior  Naris  or  Apertura  pyraformis, — air  to  the  lungs. 
Mental  Foramen,  mental  nerve  and  artery. 

POINTS  AT  THE  BASE  OF  THE  SKULL 

illustrated  and  numbered  on  fig.  25 

Median  Suture  (i), — of  the  palatine  vault,  crucial  in  form  posteriorly. 

Posterior  Nasal  Spine  (4), — the  posterior  border  of  the  palatine  vault. 

Vomer  (5), — or  nasal  septum,  its  posterior  border. 

Hamular  Process  (6), — of  the  pterygoid  process  of  the  sphenoid  bone. 

Internal  Plate  (7), — of  the  pterygoid  process  of  the  sphenoid  bone. 

External  Plate  (8), — of  the  pterygoid  process  of  the  sphenoid  bone. 

Scaphoid  Fossa  (9), — on  the  internal  plate  (7)  of  the  pterygoid  process. 

Zygoma  (13), — or  zygomatic  process  of  the  temporal  bone. 

Basilar  Suture  (14), — between  the  occipital  and  sphenoid  bones. 

Basilar  Process  (22), — of  the  occipital  bone. 

Articular  or  Clenoid  Fossa  (15), — for  the  mandible. 

Glaserian  Fissure, — squamo-tympanic. 

External  Auditory  Meatus  (16). — opening  of  the  ext.  auditory  canal. 

Mastoid  Process  (17), — of  the  temporal  bone. 

Styloid  Process  (18), — of  the  temporal  bone. 

Occipital  Condyles  (21), — articulate  with  the  atlas. 

External  Occipital  or  Nuchal  Crest  (24), — terminating  at  the  protuberance. 

Inferior  Nuchal  or  Curved  Li.ies  (25), — of  the  occipital  bone. 

BONES  OF  THE  EXTREMITIES 
THE  SHOULDER 

Bones  forming  the  Shoulder  are  the  clavicle  and  scapula  connecting  the 
arm  with  the  trunk,  and  in  this  respect  homologous  to  the  innominate  bone 
in  the  lower  part  of  the  body,  being  sometimes  called  the  shoulder  girdlet 
as  the  innominate  bones  arc  called  the  pelvic  girdle. 


CLAVICLE    AND    SCAPULA  45 

The  Clavicle,  collar-  or  key-bone,  is  a  short  bone  by  structure,  having  no 
medullary  canal.  It  is  curved  like  the  letter/,  its  inner  two-thirds  being 
prismatic  and  convex  anteriorly;  its  outer  third  flattened,  and  concave 
anteriorly.  It  is  placed  horizontally  between  the  sternum  and  the 
scapula  and  is  the  most  elastic  bone 
in  the  body.  It  presents,  from 
within  outward,  the  following  points, 
viz. — 

Facets  (6), — for  articulation  with 
the  sternum  and  the  cartilage  of 
the  1st  rib,  at  its  sternal  end. 

Upper  border  extending  the  length  of  the  medial  two-thirds,  rough  at  its 
sternal   end   for  attachment  of  the  sterno-cleido-mastoid.    Laterally  it 
becomes  lost  on  the  smooth  flat  upper  surface  of  the  acromial  third. 
UNDER  SURFACE  PRESENTS: — • 

Impression  (2), — for  the  rhomboid,  or  costo-clavicular  ligament. 

Groove  (i), — on  the  lower  surface,  for  the  subclavius  muscle. 

Tubercle, — for  the  conoid  part  of  the  costordavicular  ligament. 

Oblique  Line, — for  the  trapezoid  part  of  the  same  ligament. 

Facet  (7), — on  the  acromial  end,  for  articulation  with  the  scapula. 

Nutrient  For  amen, — in  the  subclavian  groove  or  in  posterior  surface,  and 
runs  towards  the  shoulder. 

Anterior  Border  (5), — Medial  two-thirds  convex  forwards  and  rough  for 
attachment  of  pectoralis  major.  Lateral  third  is  concave  forwards, 
presents  deltoid  tubercle  and  is  rough  for  attachment  of  deltoid. 

Posterior  Border  (4), — medial  two-thirds  concave  and  not  well-defined, 
acromial  third  is  con  vex  back  wards  and  rough  for  attachment  of  thetrape- 
zius.  Medial  two-thirds  ossify  from  cartilage,  lateral  third  from  membrane. 

•   The  Scapula,  or  shoulder-blade,  is  a  large,  flat,  and  triangular  bone, 
situated  on  the  posterior  and  lateral  portion  of  the  thorax,  from  the  2d  rib 
to  the  7th,  inclusive.     Its — 
VENTER,  or  anterior  surface,  presents  from  within  outward, — 

Ridges, — giving  attachment  to  the  subscapularis  muscle. 

Marginal  Surface,— along  the  inner  border  for  the  attachment  of  the 
serratus  magnus  muscle. 

Subscapular  Fossa  and  Angle, — for  the  subscapularis  muscle. 
DORSUM,  or  posterior  surface,  presents  the  following,  viz. — 

Spine  (10), — a  bony  ridge,  which  affords  attachment  to  the  trapezius 
and  deltoid  muscles,  and  ends  in  the  acromion  process. 

Supraspinous  Fossa  (i), — above  the  spine,  for  the^supraspinatus  muscle. 


0  HUMAN    ANATOMY 

Infraspinous.Eossa  (2), — below  the  spine,  larger  than  the  supraspinous, 
convex  at  its  centre,  lodges  the  infraspinatus  muscles,  and  the 
nutrient  foramen. 

Marginal.  Surf  ace, — along  the  external  border,  to  which  are  attached 

the  teres  minor  muscle  above,  the 
teres  major  below,  and  sometimes 
a  few  fibres  of  the  latissimus  dorsi 
at  the  lower  angle. 
Groove, — crossing  the  margin,  for  the 

dorsalis  scapulae  vessels. 
Smooth    Surface    (n), — behind     the 
root  of  the  spine,  over  which  the 
trapezius  muscle  glides. 
ACROMION  PROCESS  (12),  or  summit  of 
the  shoulder,  extends  from  the  spine, 
and  projects  over  the  glenoid  cavity, 
articulating  with  the  clavicle  by  an 
oval  facet.     It  affords  attachment  to 
the  deltoid  and  trapezius  muscles,  and 
by  its  apex  to  the    coraco-acromial 
ligament. 

CoRACpip  PROCESS  (14),  or  crow's  beak, 
projects  from  the  upper  border  and 

neck  of  the  bone  over  the  inner  and  upper  part  of  the  glenoid  cavity. 
Into  it  is  inserted  i  muscle,  the  pectoralis  minor;  the  coraco-brachialis 
and  the  short  head  of  the  biceps  arise  from  it  by  a  common  tendon, 
and  3  ligaments  are  attached  to  it, — the  conoid,  trapezoid,  and 
coraco-acromial. 

SUPERIOR  BORDER  (3)  presents  the — 

Suprascapular  Notch  (4), — converted  into  a  foramen  for  the   supra- 
scapular  nerve  by  the  transverse  ligament,  over    which  passes  the 
suprascapular,    or    transverse     scapular     artery.     The    omo-hyoid 
muscle  is  attached  to  the  border  just  internal  to  this  notch. 
AXILLARY  BORDER  (5)  is  the  thickest,  and  presents  a — 

Rough  Surface  (8), — for  the  long  head  of  the  triceps  muscle  just  below 

the  glenoid  cavity. 

Notch, — for  circumflex  scapular  artery. 
Groove, — the  origin  of  a  part  of  the  subscapularis  muscle. 
VERTEBRAL  BORDER  (9)  is  the  longest,  and  presents  an — 
Anterior  Lip, — for  the  attachment  of  the  serratus  magnus. 
Posterior  Lip, — for  the  supra-  and  infraspinatus  muscles. 


THE   HUMERUS  47 

Interspace, — between  the  lips,  for  the  levator  anguli  scapulae,  the  rhom- 
boideus   minor,   and    the  fibrous  arch  of    the    rhomboideus   major 
muscles. 
OTHER  POINTS  of  interest  on  the  bone  are  the — • 

Medial,  or  Superior  Angle, — affords  attachment  to  part  of  the  serratus 
magnus,  levator  anguli  scapulae,  and  supraspinatus  muscles. 

Inferior  Angle  (7), — affords  attachment  to  part  of  the  serratus  magnus 
and  teres  major  muscles,  and  to  a  few  fibres  of  the  latissimus  dorsi. 

Glenoid  Cavity  (6), — at  the  external  angle  or  head  of  the  bone,  a  shallow 
cavity  for  the  reception  of  the  head  of  the  humerus.  It  is  deepened 
by  the  glenoid  ligament  which  is  attached  around  its  margin;  and 
gives  origin  to  the  long  head  of  the  biceps  flexor  cubiti  muscle. 

Neck, — is  the  contracted  part  of  the  bone  behind  the  glenoid  cavity; 
from  it  arises  the  anterior  root  of  the  coracoid  process. 

THE  ARM 

The  Humerus  is  the  only  bone  in  the  arm,  and  articulates  with  the 
scapula  above,  and  with  the  ulna  and  radius  below.  It  presents  for 
examination  a  shaft  and  two  extremities,  on  which  are  the  following 
points,  viz. — 

Head  (b), — is  nearly  hemispherical,  and  smooth  for  articulation  with 
the  glenoid  cavity  of  the  scapula. 

Anatomical  Neck'(c), — is  a  constriction  in  the  bone,  just  below  the  head, 
for  the  attachment  of  the  capsular  ligament. 

Greater  Tuber osity,  or  Tubercle  (d), — has  3  small  facets  for  the  inser- 
tions of  the  supraspinatus,  infraspinatus,  and  teres  minor  muscles. 

Lesser  Tuberosity,  or  Tubercle  (e), — on  the  inner  side  of  the  bone,  gives 
insertion  to  the  subscapularis  muscle. 

Bicipital,  or  Intertubercular  Groove  (/), — lies  vertically  between  the 
tuberosities  for  the  upper  third  of  the  bone  and  lodges  the  tendon 
of  the  long  head  of  the  biceps  flexor  cubiti.  Into  its  inner  or  medial 
lip  (h)  are  inserted  the  teres  major  and  latissimus  dorsi  muscles, 
while  its  outer  or  lateral  lip  (g)  receives  the  insertion  of  the  tendon 
of  the  pectoralis  major,  which  covers  the  groove. 

Surgical  Neck, — is  situated  immediately  below  the  tuberosities,  and  is 
a  slight  constriction  in  the  upper  part  of  the  shaft. 

Shaft  (a), — is  cylindrical  above,  prismatic  and  flattened  below. 

Rough  Surface  (i), — for  the  insertion  of  the  deltoid  muscle,  about  the 
middle  of  the  external  surface  of  the  shaft. 

Musculo-spiral  Groove,  or  Sulcus  n.  Radialis  (a), — lodging  the  musculo- 
spiral,  or  radial,  nerve  and  the  superior  profunda  artery,  is  situated 


HUMAN   ANATOMY 

on  the  posterior  surface  of  the  shaft,  separating  the  origins  of  tne 
outer  and  inner  heads  of  the  triceps  muscle. 

FIG    28  Orifice  (j), — of  the  nutrient  canal,  about  the  middle  oi 

the  shaft,  on  its  internal  border. 

Condylar  Ridges, — internal  or  medial  (/>)  and  external 
or  lateral  (0),  arising  from  the  respective  condyles. 
extending  upward  along  the  shaft. 

Lateral  or  External  Condyle  (m),- -gives  attachment  to 
the  external  lateral  ligament  and  the  extensor  and 
supinator  group  of  muscles. 

Medial  or  Internal  Condyle  («), — lower  and  more  promi- 
nent lhan  the  other,  gives  attachment  to  the  internal 
lateral  ligament  and  the  flexor  and  pronator  group  of 
muscles  of  the  forearm. 

Capitellum  (&), — forms  the  outer  or  lateral  part  of  the 
inferior  articular  surface;  for  articulation  with  the 
radius,  it  is  on  the  front  of  the  lateral  condyle,  above  it 
is  the  radial  fossa. 

Trochlcar  Surface  (1), — articulates  with  the  greater 
sigmoid  cavity  (incisura  semilunaris)  of  the  ulna;  is  a 
deep  depression  between  two  borders  and  extends 
from  the  anterior  to  the  posterior  surface  of  the  bone. 

Coronoid  Fossa, — above  the  front  of-  the  trochlear  sur- 
face, receives  the  coronoid  process  of  the  ulna  when 
the  forearm  is  flexed. 
Olecranon  Fossa  (q), — above  the  back  part  of  the  trochlea,  receives  the 
tip  of  the  olecranon  process,  when  the  forearm  is  extended. 

THE  FOREARM 

The  skeleton  of  the  forearm  is -composed  of  2  bones. 
The  Ulna,  or  elbow-bone,  is  the  principal  bone  of  the  forearm.  It  is 
larger  and  longer  than  the  radius,  forming  the  greater  portion  of  the 
articulation  with  the  humerus.  It  does  not  enter  into  the  formation  of  the 
wrist-joint,  being  excluded  therefrom  by  an  interarticular  nbro-cartilage. 
It  presents  for  examination  a  shaft  and  two  extremities,  on  which  are 
the  following  points: — 

Olecranon  Process  (4), — at  the  upper  extremity,  forming  the  elbow.  It 
is  curved  forward,  its  apex  being  received  into  the  olecranon  .fossa  of 
the  humerus  when  the  forearm  is  extended.  Its  posterior  surface 
gives  insertion  to  the  tendon  of  the  triceps.  In  its  function  and 
structure  it  resembles  the  patella. 


THE    ULNA   AND   RADIUS 


49 


Coronoid  Process  (5), — below  the  olecranon  projects  forward  forming 
the  Tuberosity  (3),  its  apex  being  received  into  the  coronoid  fossa 
of  the  humerus  when  the  forearm  is  flexed.  Its  upper  surface 
is  concave  for  articulation  with  the  humerus,  its  lower  surface  rough 
for  the  insertion  of  the  brachialis  anticus  muscle.  Its  inner  surface 
has  a  margin  for  the  internal  lateral  ligament,  a  tubercle  for  the  flexor 
sublimis  digitoium,  and  a  ridge  for  the  pronator  radii  teres. 

Greater  Sigmoid  Cavity,  or  Incisura  Semilunaris  (2), — lies  between  the 
processes,  and  is  divided  by  a  vertical  ridge  into  two  unequal  parts. 
It    articulates    with   the  _trochlear  surface  of  the 
humerus.  *IG-  29' 

Lesser  Sigmoid  Cavity  or  Incisura  Radialis  (3),— lies 
external  to  the  coronoid  process;  is  oval  and  con- 
cave, articulating  with  the  head  of  the  radius,  and 
giving  attachment  to  the  orbicular  ligament. 

Shaft  (i), — large  and  prismatic  above,  smaller  and 
rounded  below,  has  the  Nutrient  Foramen  (6)  on  its 
anterior  surface  (i),  and  a  prominent  margin  ex- 
ternally, to  which  is  attached  the  interosseous 
membrane  (7).  It  gives  attachment  to  9  of  the  12 
muscles  of  the  forearm. 

Head  (8), — at  the  carpal  end,  articulates  with  the 
lesser  sigmoid  cavity  of  the  radius,  and  the  fibro- 
cartilage  of  the  wrist-joint. 

Styloid  Processes  (9),— projecting  from  the  head  in- 
ternally and  posteriorly,  its  apex  gives  attachment 
to  the  ulno  carpal  ligament  and  a  depression  at  its 
root  to  the  fibro-cartilage  of  the  joint. 

Groove, — for  the  tendon  of  the  extensor  carpi  ulnaris 


The  Radius  lies  externally  to  the  ulna  when  the  fore- 
arm is  in  supination;  it  is  prismatic  in  form  with  the  base  below  where  it 
articulates  with  the  carpus.     The  bone  is  curved  outward  and  is  shorter 
than  the  ulna,  by  the  length  of  the  olecranon.     It  presents  the  follow- 
ing points  from  above  downward,  viz. — 

Head  (n), — cylindrical  and  cup-shaped,  articulating  with  the  capitellum 
of  the  humerus,  and  the  lesser  sigmoid  cavity  or  radial  notch,  of  the 
ulna,  and  playing  within  the  orbicular  ligament. 

Neck  (12), — the  constricted  part  below  the  head. 

Bicipital   or   Radial   Tuberosity   (13), — rough   behind  lor   the  inser- 


O  HUMAN    ANATOMY 

tion  of  the  biceps,  and  smooth  in  front  where  it  is  covered  by  a 

bursa. 
Shaft  (10), — •prismoid  in  form,  presents  a  sharp  border  internally  for  the 

attachment  of  the  interosseous  membrane;  the  Nutrient  Foramen  is  on 

its  anterior  surface.     It  gives  attachment  to  8  of  the  1 2  muscles  of  the 

forearm. 

Ridge  (14), — for  the  insertion  of  the  pronator  radii  teres  muscle. 
Ulnar  Notch  or  Sigmoid  Cavity, — at  the  ulnar  side  of  the  carpal  end  (15), 

is  shallow,  and  articulates  with  the  head  of  the  ulna. 
Articular  Surface, — is  divided  by  a  ridge  into  2  facets  for  articulation 

with  the  semilunar  and  scaphoid  bones  of  the  carpus. 
Styloid  Process  (16), — gives  attachment  by  its  apex  to  the  radio-carpal 

ligament,  and  by  its  base  to  the  supinator  longus  muscle. 
Grooves, — on   the  posterior  surface   of   the  lower   extremity,    for   the 

tendons  of  the  8  extensor  muscles  of  the  thumb,  and  those  of  the  radial 

side  of  the  wrist,  and  fingers. 


THE  HAND 

The  Bones  of  the  Hand  are  divided  into  the  carpus  8,  the  metacarpus  5, 
and  the  phalanges  14.     Total,  27  bones. 


FIG.  30. 


Bones  of  the  Carpus.  The  8  bones  are. 
placed  in  2  rows,  one  row  in  front  of  the 
other,  with  4  bones  in  each  row,  as  follows, 
— the  right  hand  being  in  supination,  nam- 
ing from  without  inward,  viz. — 

i5/  or  Proximal  Row, — Scaphoid,  or 
Navicular  (s),  Semilunar,  or  Os 
Lunatum  (L),  Cuneiform,  or  Os  Tri- 
quetrum  (c),  Pisiform  (p). 
2d,  or  Distal  Row, — Trapezium,  or 
Greater  Multangular  (T),  Trapezoid  or 
Lesser  Multangular  (T),  Os  magnum, 
or  Os  Capitatum  (M),  Unciform,  or 
Os  Hamatum  (u). 


Articulations  in  the  Carpus  are  34,  as  follows: — the  number  after  each 
bone  representing  the  number  of  its  articulations,  viz. — 

Scaphoid;  5.          Semilunar,   5.  Cuneiform  3.         Pisiform,  i. 

Trapezium,  4.       Trapezoid,   4.  Os-magnum,  7.     Unciform,  5. 


CARPAL   AND   METACARPAL  BONES  5! 

Peculiarities  of  the  Carpal  Bones.  The  first  three  enter  into  the  forma- 
tion of  the  wrist-joint;  the  pisiform  does  not,  but  is  wholly  without  it,  and 
may  be  considered  a  mere  appendage  of  the  carpus.  When  the  hand  is  in 
pronation — 

The  Scaphoid  (navicular),  or  boat-shaped  bone  (S) — has  a  tuberosity 
on, its  outer  side,  its  largest  facet  is  uppermost  and  articulates  with 
the  lower  end  of  the  radius  (R).  A  transverse  groove  crosses  its 
posterior  surface  and  serves  for  the  attachment  of  ligaments. 

The  Semilunar  Bone  (os  lunatum)  (L) — has  a  crescentic  facet  externally, 
and  a  convex  facet  superiorly,  where  it  articulates  with  the  radius. 

The  Cuneiform  Bone  (os  triquetrum)  (C) — is  wedge-shaped,  its  convex 
surface  above,  articulating  with  the  interarticular  nbro-cartilage  of 
the  wrist  (F).  It  has  an  oval  facet  anteriorly  for  articulation  with 
the  pisiform. 

The  Pisiform  Bone  (os  pisiforme)  (P) — is  the  smallest,  and  has  but  one 
facet,  which  lies  posteriorly  when  the  bone  is  in  position. 

The  Trapezium  (os  multangulum  majus)  (T) — has  a  deep  groove  for  the 
tendon  of  the  flexor  carpi  radialis,  and  a  saddle-shaped  facet,  infe- 
riorly  for  the  base  of  the  ist  metacarpal. 

The  Trapezoid  (os  multangulum  minus)  (T) — is  small  and  quadrilateral, 
bent  on  itself,  with  a  saddle-shaped  facet  looking  downward,  for  the 
base  of  the  2d  metacarpal  bone. 

The  Os-magnum  (os  capitatum)  (M) — has  a  head  looking  upward,  a 
neck,  and  a  body;  is  the  largest  bone  of  the  carpus,  and  has  3  facets 
on  the  inferior  surface  for  articulation  with  the  2d,  3d,  and  4th 
metacarpal  bones. 

The  Unciform  Bone  (os  hamatum)  (U) — is  wedge-shaped,  with  a  con- 
cavity which  lies  to  the  outer  side,  and  the  unciform  process,  long  and 
curved,  projecting  from  its  palmar  surface. 

OSSA  METACARPALIA 

The  Metacarpus  consists  of  the  5  metacarpal  bones  which  are  placed 
between  the  carpus  and  the  phalanges.  They  are  long  bones,  and  each 
has  a  head,  shaft  and  base.  Their  heads  articulate  with  the  respective 
phalanges. 

The  Thumb  or  ist  Metacarpal  Bone  (i), — articulates  with  the  trapezium, 
(greater  multangular},  is  shorter  than  the  others  by  one-third,  and 
its  base  has  but  i  articular  facet. 

The  Index  or  id  Metacarpal  Bone  (2), — articulates  with  3  bones  of  the 
carpus,  the  trapezium,  (gr"ater  multangular}  trapezoid  (lesser  mult- 


52  HUMAN    ANATOMY 

angular)  and  os-magnum  (capitate) ;  its  base  is  large,  and  has  4  articu- 
lar facets. 

The  Middle  or  3^  Metacar pal  Bone  (3), — articulates  with  i  bone  of  the 
carpus,  the  os-magnum  (capitate} ;  its  base  has  a  projecting  process  on 
the  radial  side,  and  2  small  facets  on  the  opposite  side. 

The  Ring  or  tfh  Metacar  pal  Bone  (4), — articulates  with  2  bones  of  the 
carpus  and  with  the  adjacent  metacarpal  bones;  its  base  is  small  and 
has  2  circular  facets  i  on  each  side. 

The  Little  or  $th  Metacarpal  Bone  (5), — articulates  with  i  carpal  bone, 
the  unciform  (hamate},  its  base  has  i  lateral  articular  facet. 

The  Phalanges  DigitorumManus  or  finger-bones,  are  14  in  number,  3  to 
each  finger,  and  2  to  the  thumb.  They  are  long  bones,  and  each  has  a 
base,  a  shaft,  and  a  digital  extremity.  The  Bases  of  the  first  row  articu- 
late with  the  heads  of  the  metacarpal  bones.  The  Digital  Extremities  of 
the  first  and  second  rows  have  each  2  small  lateral  condyles,  while  in  the 
terminal  row  they  are  rough,  for  the  attachment  of  the  sensitive  pulp  of 
the  fingers. 

THE  THIGH 

The  Femur  or  thigh-bone,  is  the  longest,  largest  and  strongest  bone  in 
the  body,  and  is  nearly  cylindrical  in  the  greater  part  of  its  extent.  In 
the  vertical  position  of  the  skeleton  it  forms  one  side  of  a  triangle,  of  which 
the  base  is  the  breadth  of  the  pelvis,  and  the  apex  at  the  knee-joints. 
The  base  of  this  triangle  is  longest  in  the  female,  and  consequently  that 
sex  is  usually  knock-kneed.  The — 

Head  (5), — articulates  with  the  acetabulum,  forms  about  two-fifths  of 
a  sphere,  and  has  an  oval  depression  (6)  below  its  centre  for  the  attach- 
ment of  the  ligamentum  teres. 

Neck  (7), — connects  the  head  with  the  shaft,  is  pyramidal  and  flattened; 
its  obliquity  varies  with  age,  being  less  before  puberty,  about  120 
to  125  degrees  in  the  adult,  and  nearly  horizontal  to  the  shaft  in  old 
or  debilitated  subjects,  the  cancellous  bone  forming  the  neck  is 
condensed  centrally  into  a  hard  core  known  as  the  calcar  femorale. 
Great  Trochanter  (8), — a  broad,  rough,  quadrilateral  process  directed 
outward  and  backward  from  the  summit  of  the  shaft  to  within  three- 
fourths  of  an  inch  of  the  level  of  the  head.  On  its  outer  surface  the 
tendon  of  the  gluteus  maximus  plays  over  a  bursa.  It  gives  insertion 
to  the  obturator  internus,  two  gemelli,  pyriformis,  and  gluteus  mini- 
mus and  medius  muscles. 


THE   FEMUR 


53 


Trochanteric  or  Digital  Fossa  (9), — on  the  inner  or  medial  surface  of 

the  great  trochanter,  gives  insertion  to  the  obturator  externus  muscle. 
Lesser  Trochanter  (10), — at  the  inferior  root  of  the  neck  posteriorly, 

is  small  and  conical,  and  affords  insertion  to  the  tendon  of  the  psoas 

magnus   muscle,    the   tendon   of   the   iliacus 

being  inserted  immediately  below  it. 
Inter-lrochanteric  Line, — at  the  base  of  the  neck 

in   front   runs   from   one   trochanter   to   the 

other,  to  it  is  attached  the  front  part  of  the 

capsule  of  the  hip-joint. 
Inter-trochanteric  Ridge  or  Crest, — at  the  base  of 

the  neck   behind,   to   its   middle   portion  is 

attached  the  quadratus  femoris  muscle. 
Shaft, — is  slightly  curved  forward,  broad  and 

cylindrical    at    each    end,    and    narrow    and 

triangular  in  the  centre.     Its  nutrient  foramen 

perforates    its    posterior    surface    below    the 

centre,  and  is  directed  toward  the  hip.     From 

its  anterior  surface  arise  the  crureus  or  vastus- 

intermedius,    and    subcrureus    or    articularis 

genu  muscles. 
Linea  Aspera  (i),-— a  crest  lying  along  the  central 

third    of    the    shaft    posteriorly;    bifurcating 

above  (2)  towards  each  trochanter,  also  below 

(4)  towards  the  2  condyles.     To  its  outer  lip 

is  attached  the  vastus  externus,  or  lateralis, 

to  its  inner  lip,  the  vastus  internus,  or  medi- 
an's; and  between  them,  the  pectineus,  ad- 
ductor brevis,  and  gluteus  maximus  above  the 

short   head   of    the    biceps    below,    and    the 

adductors    longus    and    magnus    along    the 

greater  portion  of  the  space. 
Groove, — crossing   the  internal  condylar  ridge, 

lodges  the  femoral  artery. 
Popliteal  Space, — triangular  and  smooth,  lying  between  the  condylar 

ridges,  for  the  popliteal  artery. 
Lateral  or  External  Condyle  (n), — broader  and  shorter  than  the  internal, 

so  as  to  form  a  horizontal  articulation,  the  bone  being  inclined  towards 

the  median  line.     It  gives  attachment  to  the  external  lateral  liga- 
ment, the  popliteus,  and  the  lateral  head  of  the  gastrocnemius. 
Medial  or  Internal  Condyle  (12), — the  longer  by  half  an  inch;  it  gives 


54  HUMAN   ANATOMY 

attachment  to  the  internal  lateral  ligament  and  medial  head  of  the 

gastrocnemius  muscle. 
Intercondylar  Notch  (13), — lodges  the  crucial,  or  cruciate,  ligaments. 

In  front  the  condyles  are  continuous  with  each  other,  forming  a 

concave  depression  or  trochlea  for  the  patella. 
Lateral  Epicondyle  or  Outer  Tuberosity  (14), — on  the  external  condyle, 

for  the  attachment  of  the  external  lateral  ligament. 
Groove, — below  the  outer  tuberosity,  for  the  tendon  of  the  popliteus 

muscle,  terminating  in  a  depression  whence  the  muscle  takes  its  origin. 
Medial  Epicondyle  or  Inner  Tuberosity  (15), — on  the  internal  condyle, 

for  the  attachment  of  the  internal  lateral  ligament. 
Adductor  Tubercle, — above  the  inner  tuberosity,  for  the  insertion  of  the 

tendon  of  the  adductor  magnus  muscle. 
Depression, — behind  the  tubercle,  for  the  tendon  of  the  inner  head  of 

the  gastrocnemius. 

THE  PATELLA 

The  Patella  is  flat  and  triangularly  ovoidal  with  its  apex  directed 
downward. 

Subcutaneous  Surface, — convex,  presenting  longitudinal  ridges  and  many 
nutrient  foramina. 

Apex,— very  rough  on  its  deep  surface  for  attachment  of  ligamentum 
patellae.  Articular  surface  presents  a  longitudinal  articular  ridge 
flanked  by  concave  facets  of  which  the  lateral  one  is  the  larger.  The 
medial  facet  often  presents  a  "third  facet"  along  its  medial  border. 

THE  LEG 

The  skeleton  of  the  leg  consists  of  3  bones,  the  tibia,  the  fibula,  and  the 
patella,  the  latter  being  a  large,  sesamoid  bone  placed  in  front  of  the  knee. 

The  Tibia,  or  shin-bone,  ranks  next  to  the  femur  in  respect  to  size  and 
length.  Its  form  is  prismoidal,  the  upper  extremity  being  much  larger 
than  the  lower.  It  presents  the  following  points: — 

Head, — expands  into  two  tuberosities,  internal  (2)  and  external  (3) 
which  articulate  with  the  condyles  of  the  femur.  In  spite  of  their 
being  receiving  cavities,  the  tuberosities  of  the  tibia  are  sometimes 
called  condyles. 

Spine  or  Eminentia  Intercondyloidea  (4), — projects  vertically  between 
the  2  articular  surfaces,  is  bifid,  affording  attachment  to  the  semilunar 
fibro-cartilages  (semilunar  menisci),  and  by  depressions  in  front  and 
behind  its  base  to  the  crucial  ligaments  of  the  joint. 

Extensor  Tuberosity  (5), — on  the  head,  anteriorly  between  the  tuber- 
osities, for  the  insertion  of  the  ligamentum  patellae. 


THE   TIBIA   AND   FIBULA 


55 


Popliteal  Notch  or  Posterior  Intercondylar  Fossa, — posteriorly  between 
the  tuberosities,  affords  attachment  to  the  posterior  crucial  ligament. 

Groove, — on  the  inner  tuberosity  (2)  posteriorly,  for  the  insertion  of  the 
tendon  of  the  semi-membranosus  muscle. 

Facet, — on  the  outer  tuberosity  (3)  posteriorly  and  looking  downward, 
for  articulation  with  the  head  of  the  fibula. 

Soleus  Ridge  or  Popliteal  Line, — obliquely  across  the 
upper  part  of  the  shaft  posteriorly,  affords  attach- 
ment to  the  soleus. 

Nutrient  Canal, — the  largest  in  the  skeleton,  opens 
just  below  the  popliteal  line,  and  is  directed  down- 
ward. 

Shaft  (i), — has  3  sharp  ridges, — i  in  front,  the  Crest 
(6)  or  Shin,  and  i  on  either  side,  to  the  external  of 
which  is  attached  the  interosseous  membrane. 

Lower  Extremity  (7), — is  smaller  than  the  upper, 
grooved  posteriorly  for  the  tendon  of  the  flexor 
longus  pollicis;  externally  has  a  rough  triangular 
depression  for  articulation  with  the  fibula,  and  for 
the  attachment  of  the  inferior  interosseous  liga- 
ment. Its  inferior  surface  is  concave  and  smooth 
for  articulation  with  the  upper  surface  of  the  astrag- 
alus or  talus. 

Internal  Malleolus  (8), — projects  downward  from  the 
internal  side  of  the  lower  extremity.  It  articulates 
with  the  astragalus  (talus) ,  is  grooved  posteriorly  for 
the  tendons  of  the  tibialis  posticus  and  flexor  longus 
digitorum  muscles,  and  affords  attachment  to  the 
internal  lateral  ligament. 

The  Fibula,  is  a  long  slender  bone,  placed  nearly  parallel 
with  the  tibia  on  the  outer  side  of  the  leg.     It  is  also  called  the  Peroneus, 
or  peroneal  bone. 

Head  (10), — articulates  with  the  external  tuberosity  (lateral  condyle) 
of  the  tibia  by  a  flat  facet.  Externally,  it  has  a  prominence  for  the 
attachment  of  the  long  external  lateral  ligament  of  the  knee-joint. 

Styloid  Process,  or  Apex  Capituli, — projects  upward  from  the  head 
posteriorly,  and  gives  insertion  to  the  tendon  of  the  biceps  muscle, 
and  the  short  external  lateral  ligament  of  the  knee-joint. 

Shaft  (9), — is  twisted  about  ninety  degrees  on  its  long  axis.  It  is 
»ften  very  irregular  and  may  present  numerous  longitudinal  ridges 


56  HUMAN   ANATOMY 

which  seem  to  give  it  many  surfaces.  However,  it  always  presents 
certain  characteristics  which  are  constant.  On  the  outer  or  lateral 
surface  at  its  distal  end,  it  presents  a  long  smooth  subcutaneous 
triangle.  The  ridge  running  from  the  apex  of  this  triangle  to  the 
front  of  the  head  of  the  bone,  is  the  anterior  border  or  crest.  The 
very  first  ridge  internal  (medial)  to  anterior  border,  no  matter  how 
near  or  distant  it  may  be,  is  the  interosseous  border  or  crest.  This 
border  runs  upward  from  the  rough  interosseous  triangle  to  the 
inner  (medial)  side  of  the  head.  It  may,  for  part  of  its  length,  join 
the  anterior  border.  Running  spirally  upward  from  the  groove  for 
the  peroneal  tendons  to  the  styloid  process  (apex  capituli),  is  the 
posterior  border  (lateral  crest}.  The  interval  between  the  anterior 
border  and  the  interosseous  border,  however  narrow  it  may  be,  is  the 
extensor  surface  (anterior  part  of  the  medial  surface),  from  above 
downward  it  gives  attachment  to  extensor  digitorum  communis, 
extensor  hallucis  longus,  and  peroneus  tertius.  The  interval  be- 
tween the  anterior  border  and  the  posterior  border  (lateral  crest)  is 
the  peroneal  surface  (lateral  surface).  The  upper  third  of  this 
surface  gives  attachment  to  the  peroneus  longus,  the  middle  third, 
to  the  peroneus  brevis;  lower  third  is  free.  The  entire  interval  be- 
tween the  posterior  border  and  the  interosseous  border  is  the  flexor 
surface.  Running  from  the  back  of  the  head  downward  and  forward 
and  finally  joining  the  interosseous  border,  is  the  oblique  ridge 
(not  border)  also  called  the  medial  crest.  This  oblique  ridge 
divides  the  flexor  surface  into  two  portions;  one  which  is  close  to 
the  interosseous  border  (posterior  portion  of  the  medial  surface)  for 
the  tibialis  posticus;  the  remainder  of  the  flexor  surface  which  is 
distant  from  the  interosseous  ridge  (posterior  surface),  from  above 
downward  gives  attachment  to  the  soleus  and  flexor  hallucis  longus. 

Nutrient  Canal, — opens  about  the  centre  of  the  shaft  posteriorly,  its 
canal  running  downwards. 

External  Malleolus  (n), — is  the  lower  extremity  of  the  bone.  It  is 
larger  and  longer  than  the  internal,  articulates  with  the  astragalus  by 
a  triangular  facet,  and  is  grooved  posteriorly  for  the  tendons  of  the 
peroneus  longus  and  peroneus  brevis  muscles.  Its  edge  affords  attach- 
ment to  the  external  lateral  ligaments  of  the  ankle-joint. 

THE  FOOT 

The  Bones  of  the  Foot  are  divided  into  those  of  the  tarsus  7,  metatarsus 
5,  and  phalanges  14.     Total,  26  bones. 


THE  BONES    OF    THE   FOOT 


FIG.  33. 


Bones  of  the  Tarsus  are  placed  in  2  rows  side  by  side,  2  bones  in  the 
external  row,  5  in  the  internal,  as  follows,  viz. — 

Internally, — Astragalus  or  Talus  (5).  Scaphoid  or  Navicular  (8).  3 
Cuneiform  (10,  n,  12). 

Externally, — Os  calcis  (i),  or  Calcaneum.     Cuboid  (6). 

(The  illustration,  Fig.  33,  shows  the  plantar 
surface  of  the  skeleton  of  the  foot.) 

Articulations  in  the  Tarsus  are  28  in  num- 
ber, each  bone  articulating  with  4  others, 
except  the  os  calcis  (calcaneus),  which  articu- 
lates with  2,  and  the  external  (third)  cunei- 
form with  6  bones. 

Peculiarities  of  the  Tarsal  Bones.  They 
may  be  divided  transversely  at  the  astrag- 
al o-scaphoid-calcaneo-cuboid  articulation , 
the  site  of  Chopart's  operation.  The — 

Astragalus  or  Talus  (5), — has  a  rounded 
head,  a  convex  surface  on  which  is  a 
broad  articular  facet,  and  on  its  inferior 
surface  a  deep  groove  between  2  articu- 
lar facets. 

Os  Calcis  or  Calcaneus  (i), — is  a  large  bone, 
having  on  its  upper  surface  a  deep  groove 
for  the  interosseous  ligament,  between 
2  articular  surfaces;  anteriorly  a  large 
irregular  portion,  the  head;  and  poste- 
riorly an  elongated  portion  forming  the 
Heel  (2).  On  its  internal  surface  is  a 

projection,  the  Sustentaculum  Tali,  which  supports  the  internal 
articulating  surface;  below  which  process  the  bone  is  deeply  grooved 
for  the  plantar  vessels  and  nerves  and  the  flexor  tendons.  To  the  os 
calcis  are  attached  8  muscles  and  the  plantar  fascia. 

Navicular  or  Scaphoid  Bone  (8), — is  boat-shaped,  has  3  facets  anteriorly 
for  the  cuneiform  bones,  a  concave  surface  posteriorly  for  the  astrag- 
alus, and  a  facet  externally  for  the  cuboid  bone.  A  tubercle  (9)  is 
situated  on  the  lower  surface  internally,  for  the  insertion  of  the  tibialis 
posticus  muscle. 

Cuboid  Bone  (6), — has  3  articular  surfaces,  and  a  groove  inferiorly  for 
the  tendon  of  the  peroneus  longus. 

Internal  or  First  Cuneiform  Bone  (10),  the  largest  of  the  3,  has  a  tubercle 


EJAL.9, 


58  HUMAN    ANATOMY 

on  its  plantar  surface  for  the  insertion  of  parts  of  the  tendons  of  the 

tibialis  anticus  and  tibialis  posticus  muscles. 
Middle  or  Second  Cuneiform  Bone  (n), — is  small  and  wedge-shaped  with 

the  narrow  end  downward.     Its   anterior  surface  is   considerably 

behind  the  line  of  the  tarso-metatarsal  articulation,  thus  forming  a 

recess  into  which  the  base  of  the  second  metatarsal  bone  fits. 
External  or  Third  Cuneiform  Bone  (12), — is  also  wedge-shaped,   but 

longer  than  the  middle  one;  and  affords  origin  to  i  muscle,  the  flexor 

brevis  pollicis. 

The  Metatarsus  consists  of  5  metatarsal  bones,  which  are  long  bones, 

having  each  a  shaft  and  two  extremities.     Their  bases  articulate  with  the 

tarsal  bones  and  with  each  other;  their  heads  with  the  first  row  of  phalanges. 

ist  Metatarsal  (i3),: — is  large  but  shorter  than^the  others,  and  forms  the 

inner  border  of  the  foot,  articulating  with  the  internal  cuneiform. 

The  head  is  large  and  has  two  grooved  facets  on  its  plantar  surface, 

over  which  glide  2  sesamoid  bones  (19). 
2d  Metatarsal  (14), — is  the  longest;  its  base  has  3  facets  for  articulation 

with  the  3  cuneiform  bones  in  the  recess  formed  by  the  shortness  of 

the  middle  or  second  cuneiform. 
•$d  Metatarsal  (15), — has  2  facets  on  the  inner  side  of  its  base,  besides 

the  facets  for  the  internal  cuneiform  and  the  4th  metatarsal  bone. 
4th  Metatarsal  (16), — articulates  with  the  cuboid  bone,  and  also  with  the 

internal  or  first  cuneiform. 
^th  Metatarsal  (17), — articulates  obliquely  with  the  cuboid  bone,  and 

has  a  tubercular  projection  (18)  on  the  outer  surface  of  its  base,  which 

forms  the  guide  in  Key's  operation. 

The  Phalanges  of  the  Foot  number  14  as  in  the  hand,  the  great  toe 
having  two  (20,  21),  the  other  toes  three  each.  They  are  long  bones, 
each  having  a  base,  a  shaft,  and  an  anterior  extremity.  They  are  convex 
above,  concave  below,  and  articulate  by  the  bases  of  the  first  row  with  the 
bones  of  the  metatarsus.  The  anterior  extremities  of  the  distal  phalanges 
(21,  23)  are  expanded  into  surfaces  for  the  support  of  the  nails  and  pulp 
of  the  toes. 

THE  ARTICULATIONS 

An  Articulation  or  Joint  is  a  connection  between  two  bones  of  the  skele- 
ton, and  has  entering  into  its  formation  the  following-named  structures  — 
bone,  cartilage,  fibro-cartilage,  ligament  and  synovial  membrane. 


ARTICULATIONS 

Articulations  are  divided  into  three  classes, — Synarthrosu,  immovable 
joint;  Amphiarthrosis,  mixed  articulation,  having  limited  motion;  and 
Diarthrosis,  movable  joint,  having  free  motion. 

Synarthroses  are  subdivided  into — Sutura,  formed  by  processes  and  in- 
dentations; Schindy'lesis,  by  a  plate  of  bone  entering  into  a  fissure  of  an- 
other; and  Gompho'sis,  by  a  conical  process  into  a  socket.  The  Sutura  are 
again  subdivided  into — S.  dentata,  having  tooth-like  processes;  S.  serrata, 
with  serrated  edges;  S.  limbosa,  having  beveled  margins  and  dentated  proc- 
esses; S.  squamosa,  with  thin  beveled  margins  overlapping  each  other;  S. 
harmonia,  contiguous  rough  surfaces  opposed  to  each  other.  The  first  3 
are  also  named  Sutura  Vera  (true  sutures)  having  indented  borders;  the 
last  2  Sutura  Notha  (false  sutures)  being  formed  by  rough  surfaces. 

Amphiarthroses  are  subdivided  into — Symphysis,  connected  by  fibro- 
cartilage  and  not  separated  by  synovial  membrane;  Syndesmosis,  united 
by  an  interosseous  ligament. 

Diarthroses  are  subdivided  into — Ginglymus,  hinge-joint;  Trochoides, 
pivot-joint,  formed  by  a  ring  surrounding  a  pivot;  Condyloid,  by  an  ovoid 
head  in  an  elliptical  cavity;  Reciprocal  Reception,  saddle-joint,  by  surfaces 
inversely  convex  and  concave;  Enarthrosis,  ball-and-socket  joint;  Arthrodia, 
gliding  joint. 

Examples  of  each  of  the  above-named  articulations,  as  follows: — 
Synarthrosis, — joints  of  the  cranium  and  face,  except  the  lower  jaw. 

Sutura  Dentata, — the  inter-parietal  suture. 

Sutura  Serrata, — the  inter-frontal  suture. 

Sutura  Limbosa, — the  fronto-parietal  suture. 

Sutura  Squamosa, — the  temporo-parietal  suture. 

Sutura  Harmonia, — the  intermaxillary  suture. 

Schindylesis, — rostrum  of  sphenoid  with  the  vomer. 

Gomphosis, — the  teeth  in  their  alveoli. 
Amphiarthrosis, — the  joints  between  the  bodies  of  the  vertebras  (sym- 

physes),  the  inferior  tibio-fibular  articulation  (syndesmosis). 
Diarthrosis,  movable  joint,  as  follows: — 
— -Ginglymus, — inter-pharyngeal  joints  and  the  elbow-joint. 
——Trochoides, — superior    radio-ulnar,    atlanto-axial    joint.     (Articulatio 
Atlanto-epistrophica.) 

Condyloid, — the  wrist-joint. 

Reciprocal  Reception, — the  carpo-metacarpal  joint  of  the  thumb. 

Enarthrosis, — the  hip-  and  shoulder-joints. 

Arthrodia, — the  carpal  and  tarsal  articulations. 


OO  HUMAN   ANATOMY 

Varieties  of  Motion  in  Joints  are  4  in  number,  viz. — gliding,  angular 
movement  (including  adduction,  abduction,  flexion  and  extension), 
circumduction  and  rotation.  These  movements  are  often  more  or  less 
combined  in  the  various  joints. 

Structures  entering  into  the  formation  of  Joints  are  5,  viz., — the 
articular  lamella  of  bone,  cartilage,  fibro-cartilage,  ligaments  and  synovial 
membrane. 

Articular  Lamella  of  Bone — differs  from  ordinary  bone  tissue  in  being 
more  dense,  containing  no  Haversian  canals  nor  canaliculi,  and  having 
larger  lacunae. 

Cartilage, — a  non-vascular  structure,  is  divisible  into  temporary  and 
permanent  varieties.  The  first  forms  the  original  frame-work  of  the 
skeleton,  and  becomes  ossified.  Permanent  cartilage  is  not  prone 
to  ossification,  and  is  divided  into  4  groups, — Articular,  covering  the 
ends  of  bones  in  joints;  Inter  articular,  between  the  bones  in  a  joint; 
Costal,  forming  part  of  the  skeleton;  and  Membraniform.  According 
to  its  minute  structure,  cartilage  is  divided  into  Hyaline  Cartilage, 
White  Fibro-cartilage  and  Yellow  or  Elastic  Fibro-cartilage. 

Fibro-cartilages, — in  joints  and  osseous  grooves  are  of  the  white  variety 
and  may  be  arranged  in  4  groups,  the — Inter  articular  (menisci) ,  separat- 
ing the  bones  of  a  joint;  Connecting,  binding  bones  together;  Circum- 
ferential, deepening  cavities;  Stratiform,  lining  grooves. 

Ligaments — are  bands  of  white  fibrous  tissue,  except  the  ligamenta 
subflava  and  the  ligamentum  nuchse,  which  consist  entirely  of  yellow 
elastic  tissue. 

Synovial  Membranes — secrete  the  synovia,  a  viscid,  glairy  fluid,  and 
resemble  the  serous  membranes  in  structure.  They  are  Articular, 
lubricating  joints;  Bursal,  forming  closed  sacs  (bursae),  interposed 
between  surfaces  which  move  upon  each  other;  Vaginal,  ensheathing 
tendons. 

ARTICULATIONS  OF  THE  TRUNK 

The  Temporo-mandibular  Articulation  is  a  ginglymo-arthrodial  joint 
between  the  condyle  of  the  lower  jaw  and  the  anterior  part  of  the  glenoid 
cavity  of  the  temporal  bone.  It  has  2  synovial  membranes  with  an 
interarticular  fibro-cartilage  between  them,  and  4  ligaments,  viz. — 

External  Lateral, — from  the  tubercle  of  the  zygoma  to  the  outer  side  of 
the  neck  of  the  condyle  of  the  lower  jaw. 

Spheno-mandibular  or  Internal  Lateral  (d), — from  the  alar  spine  of  the 


ARTICULATIONS    OF    THE    TRUNK 


6l 


PIG.  34- 


sphenoid  to  the  mandibular  spine  or  lingula  on  the  margin  of  the 
dental  foramen. 
Stylo-mandibular  (/), — from  the  styloid  process  of  the  temporal  bone  tc 

the  angle  and  posterior  border  of  the  ramus  of  the  lower  jaw. 
Capsular  (c), — from  the  edge  of  the  glenoid  cavity  and  the  eminentia 

articularis  to  the  neck  of  the  condyle  of  the  lower  jaw. 
Its  Nerves  are  derived  from  the  auriculo- 
temporal  and  masseteric  branches  of  the 
mandibular.     Arteries  from  the  temporal 
branch  of  the  external  carotid. 
The  Vertebral  Articulations  are  formed  by 
the  adjacent  surfaces  of  the  bodies   of  the 
vertebrae    and  their  processes,  and  are  con- 
nected by  the  following  ligaments,  etc. — 
'     Anterior  Common  Ligament  (i), — along  the 

fronts  of  the  bodies. 
f\\  Posterior    Common    Ligament, — along    the 

backs  of  the  bodies. 

2J  Ligamenta  Subflava, — connect   the  laminae  of  adjacent  vertebrae. 
If  I  Capsular  (4), — surround    the    articular    processes    and   are   lined  by 
synovial  membrane. 


^j 


Supra-spinous    and      nter-spinous, 


FIG.  35. 


—  connect    the  spinous    processes. 

In  the  cervical  region  they  form 

what  is  called  the  Ligamentum 

Nuchae. 
Inter-transverse    (3),  —  connect   the 

transverse  processes. 
Intervertebral  Substance,  —  in  lentic- 

ular disks  between  the  bodies  of 

the  vertebrae,  from  the  axis  to 

the  sacrum. 


The  Atlanto-axial  Articulation  is 
a  double  arthrodia  or  gliding  joint 
between  the  articular  processes  and 

a    pivot  articulation  between  the  atlas  and  the  odontoid  process.     It 
has  6  ligaments  and  4  synovial  membranes,  as  follows:  — 
Anterior  2,  and  Posterior  i,  Atlanto-axial,  —  -continuations  of  the  anterior 

and  posterior  common  spinal  ligaments. 

Capsular  2,  —  surrounding  the  articular  surfaces,  each  lined  by  a  synoviai 
membrane. 


62 


HUMAN   ANATOMY 


PIG.  36. 


Transverse  Ligament, — divides  the  spinal  foramen  of  the  atlas  into  two 
portions,  stretching  across  between  the  tubercles  on  the  inner  sides  of 
the  articular  processes.  It  holds  the  odontoid  process  in  place,  having 
a  synovial  membrane  interposed.  Another  synovial  membrane  is 
situated  between  the  process  and  the  anterior  arch.  The  transverse 
ligament  sends  two  vertical  slips,  one  upward,  the  other  downward, 
from  which  it  is  often  named  the  Cruciform  Ligament. 

The  Occipito-atlantal  Articulation  is  a  double  condyloid  formed  by  the 

condyles  of  the  occipital  bone  with  the 
superior  articular  surfaces  of  the  atlas, 
and  has  6  ligaments,  viz. — 

Anterior  Occipito-atlantal  (a), — from 
the  anterior  margin  of  the  fora- 
men magnum  to  the  anterior  arch 
of  the  atlas. 

Posterior  Occipito-atlantal, — from  the 
posterior  margin  of  the  foramen 
magnum  to  the  posterior  arch  of 
the  atlas.  It  is  perforated  by  the 
vertebral  and  suboccipital  nerves. 
Lateral  2, — from  the  jugular  processes  of  the  occipital  bone  to  the  bases 

of  the  transverse  processes  of  the  atlas. 

Capsular  2  (d), — around  the  articular  surfaces,  lined  by  synovial  mem- 
brane. 

The  Occipito-axial  Articulation  is  formed  by  the  occipital  bone  and  the 
odontoid  process  of  the  axis,  which  do  not  articulate  with  each  other 
strictly,  but  are  connected  with  4  ligaments,  the — 

Occipito-axial  (i)  (Membrana  Tectoria), — a  continuation  of  the  posterior 

common  spinal  ligament  to  the  basilar  process  of  the  occipital  bone. 

Lateral  Occipito-odontoid    (5)    (Check  Ligaments}  2, — from  the  head  of 

the  odontoid  process  to  the  inner  sides  of  the  occipital  condyles. 
Middle  Odontoid  (Ligamentum  Suspensorium), — from  the  anterior  mar- 
gin of  the  foramen  magnum  to  the  odontoid  apex. 
The  Costo-vertebral  Articulations  are  each  a  double  arthrodia  between 
the  head  of  the  rib  and  the  bodies  of  2  adjacent  vertebrae,  except  in  the 
ist,  roth,  nth,  and  i2th  ribs,  which  are  single,  as  they  articulate  with 
but  i  vertebra  each.     Their  ligaments  are  3,  viz. — 

Anterior  Costo-central  (2),  or  Stellate  Ligament, — consists  of  3  bundles, 
which  fasten  the  anterior  part  of  the  head  of  the  rib  to  the  inter- 
vertebral  disk  and  the  2  adjacent  bodies. 


ARTICULATIONS    OF   THE   TRUNK  63 

Intra-articiilar, — in  the  interior  of  the  joint,  from  the  crest  on  the  head 
of  the  rib  to  the  intervertebral  disk;  on  each  side  there  is  a  separate 
synovial  membrane.  In  the  ist,  loth,  nth  and  i2th  ribs  it  does  not 
exist,  hence  there  is  but  one  synovial  membrane. 

Capsular, — surrounding  the  articular  surfaces. 

The  Costo-transverse  Articulations  are  10  arthrodial  articulations 
between  the  tubercles  of  the  first  10  ribs  and  the  transverse  processes  of  the 
vertebrae  next  below.  Their  ligaments  are  4,  viz. — Anterior  superior, 
Middle  (interosseous),  Posterior  Costo-transverse  and  Capsular. 

The  Chondro-sternal  Articulations  are  7  in  number,  i  of  which  (the 
first)  is  a  synarthrodial  and  6  are  arthrodial  articulations,  between  the 
costal  cartilages  and  the  margin  of  the  sternum.  The  first  has  no  synovial 
membrane,  the  second  only  has  an  intra-articular  ligament.  Each  has  4 
ligaments, — the  Anterior  and  Posterior  Chondro-sternal,  a  Capsular,  and  an 
Inter  articular.  The  Chondro-xiphoid  Ligaments  connect  the  xiphoid  ap- 
pendix to  the  cartilage  of  the  6th  or  7th  rib. 

The    Costo-chondral    and   Interchondral   Articulations   connect    the 

costal  cartilages  with  the  ribs  and  with  each  other  respectively.  With 
the  ribs  by  a  depression  on  the  end  of  each  rib,  strengthened  by  the 
blending  together  of  the  periosteum  and  the  perichondrium.  The  6th, 
7th  and  8th,  and  sometimes  the  pth  and  loth  costal  cartilages  articulate 
with  each  other  by  their  borders  and  each  has  a  Capsular  and  an  Inter- 
chondral ligament,  with  3  synovial  membranes  for  the  3  articulations 
between  the  6th  and  the  pth  cartilages. 

The  Ligaments  of  the  Sternum  are  an  Anterior  Sternal  and  a  Posterior 
Sternal  ligament,  with  a  layer  of  cartilage  between  the  manubrium  and  the 
gladiolus. 

The  Sacro-vertebral    Articulation  is  similar  to  the    other  vertebral 
articulations,  but  has  2  additional  ligaments  on  each  side,  the — 
Lumbo-sacral, — from  the  transverse  process  of  the  5th  lumbar  vertebra 

.to  the  base  of  the  sacrum  laterally  and  anteriorly. 
Ilio-lumbar, — from  the  apex  of  the  transverse  processes  of  the  5th 

lumbar  vertebra  to  the  crest  of  the  ilium  in  front  of  the  sacro-iliac 

articulation. 

The  Sacro-coccygeal  Articulation  is  an  amphiarthrodial  joint,  and  has 
4  ligaments,  viz. — 

Anterior  Sacro-coccygeal. 
Posterior  Sacro-coccygeal. 


64 


HUMAN    ANATOMY 


Two  Lateral  Sacro-coccygeal. 
Fibro-cartilage,  interposed  in  the  joint. 

The  Sacro-iliac  Articulation  is  an  amphiarthrodial  joint,  formed  by  the 
lateral  surfaces  of  the  sacrum  and  ilium.  Its  ligaments  on  each  side  are 
the— 

Anterior  Sacro-iliac. 

Posterior  Sacro-iliac  (8), — which  consists  of  a  short  transverse  part 
(8)  and  a  long  part  known  as  the — 
Oblique  Sacro-iliac. 

The  Sacro-ischiatic  Articulation  is 
an  amphiarthrosis  between  the  sa- 
crum and  the  ischium.  Its  liga- 
ments convert  the  sacro-sciatic 
notches  into  foramina,  the  greater 
notch  (5)  being  crossed  by  the  lesser 
ligament,  the  lesser  notch  (6)  by  the 
greater  ligament.  These  foramina 
are  described  on  page  13  ante. 

Posterior  or  Great  Sacro-sciatic 
Ligament  (1.  sacrotuberosum) 
(13),  is  the  divorced  tendon  of 
the  biceps  femoris  muscle,  it  ex- 
tends from  the  posterior  inferior 
spine  of  the  ilium  and  the  pos- 
terior surface  and  margins  of 
the  sacrum  and  coccyx  (2),  to 
the  inner  margin  of  the  tuber- 

csity  (4)  and  the  ascending  ramus  (14)  of  the  ischium,  the  latter  por- 
tion being  known  as  the  Falciform  Ligament. 

Anterior  or  Lesser  Sacro-sciatic  Ligament  (1.  sacrospinosum)  (15), — from 
the  margins  of  the  sacrum  and  coccyx,  into  the  spine  of  the  ischium 
(16). 

The  Pubic  Articulation  or  Symphysis  Pubis,  is  an  amphiarthrodial 
joint  formed  by  the  junction  of  the  two  pubic  bones  with  each  other. 
It  has  an  interpubic  disk  and  4  ligaments,  the — 

Anterior  Pubic.  Posterior  Pubic.  Superior  Pubic 

Sub-pubic,  forming  a  fibrous  arch  between  the  rami. 

ARTICULATIONS  OF  THE  UPPER  EXTREMITY 
The  Sterno -clavicular  Articulation  is  an  arthrodial  joint,  formed  by 
the  sternal  end  of  the  clavicle  with  the  sternum  and  the  cartilage  of  the  ist 


ARTICULATIONS    OF    UPPER    EXTREMITY 


the 


FIG.  38. 


rib.     It  has  an  interarticular  fibro-cartilage,  2  synovial  membranes  and  5 
ligaments,  the — 

Anterior  Sterno-clavicidar.  Inter  clavicular. 

Posterior  Ster  no-clavicular.  Costo-clavicular  or  Rhomboid. 

Capsular, — Formed  by  the  anterior  and  posterior. 

The  Acromio-clavicular  Articulation  is  an  arthrodial  joint,  formed  by 
the  outer  extremity  of  the  clavicle  and  the  acromion  process  of  the  scapula. 
It  frequently  has  an  interarticular  fibro-cartilage  and  2  synovial  mem- 
branes (usually  but  i  is  present).  It  has  3  ligaments,  the — 
Superior  Acromio-clavicular(i}.  Coraco-clavicular(2)  j Trapezoid,  externally. 
Inferior  Acromio-clavicular.  divided  into —  I.  Conoid,  internally. 

Proper  Ligaments  of  the  Scapula  are  2,  the  Coraco-acromial,  and  the 
Transverse,  as  follows: — 

Coraco-acromial   (3), — completes   the   vault    partially   formed   by 
coracoid  and  acromion  processes  over  the  head  of  the  humerus. 
Transverse   (4), — from  the  base   of    the 
coracoid  process  to  the  margin  of  the 
suprascapular  notch,  converting  it  into 
a  foramen  for  the  suprascapular  nerve. 
The  Shoulder- joint,  Articulatio  Humeri, 
is  an  enarthrodial  or  ball-and-socket  joint, 
formed  by  the  head  of  the  humerus  and  the 
glenoid   cavity   of    the  scapula.     It  has  a 
Synovial  Membrane  which  is  reflected  upon 
the  tendons  of  the  biceps,  subscapularis, 
and  infraspinatus  muscles,  and  communi- 
cates with  bursae  beneath  the  2  latter  ten- 
dons.    Its   Arteries  are  derived  from  the 
anterior   and   posterior  circumflex  and  the 
suprascapular;  its  Nerves  from  the  circum- 
flex  (n.  axillaris)  and    the    suprascapular. 
It  has  3  ligaments,  the — 

Capsular   (5),  from  the   margin  of  the 

glenoid  cavity  to  the  anatomical  neck  of  the  humerus;  has  3  open- 
ings for  the  reflexions  of  the  synovial  membrane  over  the  tendons. 
Coraco-humeral  (6),  intimately  united  with  the  capsular,  extends  from 

the  coracoid  process  to  the  greater  tuberosity  of  the  humerus. 
Glenoid,  a  fibre-cartilaginous  ring,  continuous  above  with  the  tendon  of 
the  long  head  of  the  biceps  (7),  and  attached  around  the  margin  of 


66 


HUMAN    ANATOMY 


FIG.  39 


the  glenoid  cavity  in  order  to  deepen  the  articular  surface  and  pad 
its  edge. 

The  Elbow-joint,  Articulatio  Cubiti,  is  a  ginglymus  or  hinge  articulation, 
formed  by  the  lower  end  of  the  humerus  with  the  greater  sigmoid  cavity 
of  the  ulna  (2)  and  the  head  of  the  radius  (3).  Its  Synovial  Membrane 
is  reflected  over  the  ligaments,  and  includes  the  superior  radio-ulnar 
articulation.  Its  Arteries  are  derived  from  the  anastomotica  magna, 
brachial,  radial,  ulnar,  and  interosseous  recurrent,  superior  and  inferior 
profunda  arteries.  Its  Nerves  are  branches  of  the  ulnar,  the  musculo- 
cutaneous  and  the  median.  It  has  4  ligaments,  the — 

Anterior, — from  the  internal  condyle  (7)  and  anterior 
surface  of   the  humerus  to  the  orbicular  ligament 
of  the  radius  and  the  coronoid  process  of  the  ulna. 
Posterior    (6), — from    the    posterior   surface    of    the 

humerus  to  the  olecranon  process  of  the  ulna. 
External  Lateral  (1.  collaterale  radiale)  (4), — from  the 
external  condyle  of  the  humerus  passing  obliquely 
downward  and  backward  behind  the  orbicular 
ligament  and  the  head  of  the  radius  to  be  attached 
strongly  to  the  ulna  at  a  point  opposite  the  attach- 
ment of  the  internal  lateral  ligament. 
Internal  Lateral  (1.  collaterale  ulnare), — from  the  in- 
ternal condyle  of  the  humerus  (7)  to  the  inner  side 
of  the  juncture  of  the  coronoid  and  olecranon  proc- 
,ess£^of  the  ulna. 

The  Radio-ulnar  Articulations  are  3  in  number,  as 
follows: — 

SUPERIOR  RADIO-ULNAR  ARTICULATION — is  a  trochoid 
or  pivot-joint,  formed  by  the  head  of  the  radius  and  the 
lesser  sigmoid  cavity  of  the  ulna.     Its  synovial  mem- 
brane is  a  continuation  of  that  in  the  elbow-joint.     It 
has  only  one  ligament,  the — 
Orbicular  Ligament  (5),  consists  of  two  distinct  portions,  the  orbicular 
and   the  capsular.     The  orbicular    portion  is  very    thick, — forms 
four-fifths  of  a  circle  and  surrounds  the  neck  of  the  radius.     It  is 
attached  to  the  margins  of  the  lesser  sigmoid  cavity  of  the  ulna,  and 
to  the  external  lateral  ligament  of  the  elbow-joint.     The  Capsular 
portion  is  loose  and  thin,  its  fibres  run  from  the  lower  margin  of  the 
true  orbicular  ligament  to  the  neck  of  the  radius. 
MIDDLE  RADIO-ULNAR  ARTICULATION — is  formed  by  the  shafts  of  the 


ARTICULATIONS    OF    UPPER   EXTREMITY  67 

radius  and  ulna,  which  do  not  touch  each  other,  but  are  connected  by  2 
ligaments,  as  follows: — 

Oblique  Ligament, — from  the  tubercle  at  the  base  of  the  coronoid  process 
of  the  ulna  to  the  shaft  of  the  radius.  Its  fibres  run  from  the  ulna 
obliquely  downward  to  the  radius,  whereas  the  fibers  of  the  inter- 
osseous membrane  run  from  the  radius  downwards  to  the  ulna. 
Interosseous  Membrane  (9), — -obliquely  downward  from  the  interosseous 
ridge  on  the  radius  to  that  on  the  ulna.  Through  the  interval  between 
its  upper  border  and  the  oblique  ligament,  the  posterior  interosseous 
vessels  pass. 

INFERIOR  RADIO-ULNAR  ARTICULATION — is  a  pivot-joint,  formed  by  the 
head  of  the  ulna  and  the  sigmoid  cavity  of  the  radius.  Its  Synovial 
Membrane  (membrana  sacciformis)  is  very  loose,  and  sometimes  com- 
municates with  that  of  the  wrist-joint  through  an  opening  in  the  triangular 
fibro-cartilage  which  separates  the  head  of  the  ulna  from  the  wrist-joint. 
It  is  a  capsule  but  is  often  considered  as  consisting  of  two  portions  which 
are  then  called, 

Anterior  Radio-ulnar.  Posterior  Radio-ulnar. 

++- 

The  Radio-carpal  Articulation,  or  Wrist-joint,  is  a  condyloid  articula- 
tion formed  by  the  lower  end  of  the  radius  and  the  triangular  fibro-cartilage 
with  the  scaphoid  (os  naviculare),  semilunar  (os  lunatum),  and  cuneiform, 
(os  triquetrum)  bones  of  the  carpus.  Its  Arteries  are  the  anterior  and  pos- 
terior carpal  from  both  the  radial  and  ulnar,  the  anterior  and  posterior 
interosseous  and  ascending  branches  from  the  deep  palmar  arch.  Its 
Nerves  are  derived  from  the  ulnar  and  posterior  interosseous.  It  is  lined 
by  a  synovial  membrane,  and  is  connected  by  a  capsule,  which  is  divided 
into  the  following-named  4  ligaments,  the — 

External  Lateral  (radio-carpal).  Anterior  Ligament. 

Internal  Lateral  (ulno-carpal).  Posterior  Ligament. 

The  Carpal  Articulations  are  in  3  sets, — between  the  bones  of  the 
first  row,  between  the  bones  of  the  second  row,  between  the  2  rows  of 
bones  with  each  other. 

The  scaphoid,  semilunar,  and  cuneiform  bones  are  connected  together 
by  Dorsal,  Palmar  (volar),  and  2  Inter  osseous  Ligaments.  The  pisiform 
bone  has  a  separate  capsular  ligament  and  synovial  membrane  and  2 
Palmar  Ligaments  connecting  it  with  the  unciform  and  the  5th 
metacarpal. 

The  4  bones  of  the  second  row  are  connected  together  by  Dorsal, 
Palmar  and  3  Interosseous  Ligaments. 


68  HUMAN    ANATOMY 

The  two  rows  of  bones  are  united  to  each  other  by  Dorsal,  Palmar,  and 
2  Lateral  Ligaments,  the  last  named  being  continuous  with  the 
lateral  ligaments  of  the  wrist-joint. 

The  Carpo-metacarpal  Articulations.  That  of  the  thumb  with  the 
trapezium  is  a  joint  of  reciprocal  reception,  and  has  a  Capsular  Ligament 
and  a  separate  synovial  membrane.  The  4  inner  metacarpal  bones  form  4 
arthrodial  joints  with  the  adjacent  carpal  bones  by  6  Dorsal,  8  Palmar,  and 
2  Interosseous  Ligaments,  irregularly  disposed. 

The  Synovial  Membranes  of  the  Wrist  are  5  in  number,  and  are  situated 
as  follows: — • 

The  First,  or  Membrana  Sacciformis, — between  the  head  of  the  ulna, 
the  sigmoid  cavity  of  the  radius,  and  the  triangular  interarticular 
fibro-cartilage. 

The  Second, — between  the  lower  end  of  the  radius,  the  triangular  fibro- 
cartilage,  and  the  scaphoid,  semilunar,  and  cuneiform  bones  of  the 
carpus. 

The  Third, — between  all  the  carpal  bones  except  the  pisiform  and 

between  the  bases  of  the  inner  4  metacarpal  bones;  but  it  extends 

only  halfway  into  the  2  intervals  between  the  3  proximal  bones  of  the 

carpus. 

The  Fourth, — between  the  trapezium  and  the  metacarpal  bone  of  the 

thumb. 

The  Fifth, — between  the  cuneiform  and  pisiform  bones. 
The  Metacarpo-metacarpal  Articulations.     The  4  inner   metacarpal 
bones  are  connected  together  at  their  bases  by  Dorsal,  Palmar,  and  Inter, 
osseous  Ligaments,  and  at  their  digital  extremities  by  the   Transverse 
Ligament,  a  narrow  fibrous  band  which  crosses  them  anteriorly. 

Remaining  Articulations  of  the  Hand.  The  metacarpo-phalangeal 
are  condyloid  joints  formed  by  the  rounded  heads  of  the  metacarpal  bones 
and  the  shallow  cavities  in  the  extremities  of  the  first  phalanges.  The 
phalangeal  articulations  are  ginglymus  joints.  Both  sets  have  for  each 
joint  an  Anterior  and  2  Lateral  Ligaments,  the  former  being  lined  each  with 
a  synovial  membrane.  There  are  no  posterior  ligaments  to  these  articula- 
tions, the  extensor  tendons  of  the  hand  supplying  their  places. 

ARTICULATIONS  OF  THE  LOWER  EXTREMITY 

The  Hip-joint  is  a  true  enarthrodial  or  ball-and-socket  articulation, 
formed  by  the  head  of  the  femur  with  the  acetabulum  of  the  os  innom- 
inatum.  Its  Synovial  Membrane  is  extensive,  investing  most  of  the 


ARTICULATIONS    OF   LOWER   EXTREMITY  69 

head  and  neck  of  the  femur,  the  capsular,  cotyloid  and  teres  ligaments,  and 
the  cavity  of  the  acetabulum.  Its  Arteries  are  derived  from  the  obturator, 
sciatic,  internal  circumflex,  and  gluteal.  Its  Nerves  are  branches  from  the 
sacral  plexus,  great  sciatic,  obturator,  and  accessory  obturator.  It  has  5 
ligaments  as  follows:  the — 

Capsular, — from  the  margin  of  the  acetabulum  and  the  transverse  liga- 
ment into  the  base  of  the  neck  of  the  femur  above,  the  anterior  inter- 
trochanteric  line  in  front,  and  to  the  middle  of  the  neck  of  the  bone, 
behind.  Superadded  to  and  strengthening  it  are  3  auxiliary  bands, 
the  fibres  of  which  form  part  of  the  capsule, — the  ilio-femoral  (de- 
scribed below),  the  ischio-femoral  and  the  pectineo- femoral  bands. 
Ilio-femoral  or  Y -ligament, — from  the  anterior  inferior  spine  of  the  ilium, 
into  the  anterior  inter-trochanteric  line  by  two  fasciculi.  It  is  a 
dissected  portion  of  the  capsular  ligament  which  is  very  strong 
anteriorly. 

Ligamentum  Teres, — from  a  depression  on  the  head  of  the  femur  into  the 
margins  of  the  cotyloid  notch  of  the  acetabulum  and  into  the  trans- 
verse ligament,  by  two  fasciculi. 
Cotyloid, — a  fibro-cartilaginous  band  surrounding  the  margin  of  the 

acetabulum  in  order  to  deepen  its  cavity  and  pad  its  edge. 
Transverse, — that  part  of  the  cotyloid  ligament  which  crosses  over  the 
cotyloid  notch  converting  it  into  a  foramen. 

The  Knee-joint  is  a  complicated  articulation,  formed  by  the  condyles  of 
the  femur  with  the  head  of  the  tibia  and  the  patella  in  front.  It  consists  of 
3  articulations  in  one;  those  between  the  condyles  of  the  femur  and  the 
tuberositis  of  the  tibia  are  condylar  joints,  while  that  between  the  patella 
and  the  femur  is  partly  trochlear.  Its  Synomal  Membrane  is  the  largest 
in  the  body,  being  reflected  for  2  or  3  inches  over  the  anterior  surface  of  the 
femur,  where  it  is  supported  by  the  subcrureus  muscle;  also  over  its  con- 
dyles, the  patella,  semilunar  cartilages,  crucial  ligaments,  and  the  head  of 
the  tibia;  and  it  is  prolonged  through  an  opening  in  the  capsular  ligament 
beneath  the  tendon  of  the  popliteus.  Its  Arteries  are  derived  from  the 
anastomotica  magna,  the  articular  branches  of  the  popliteal,  the  recurrent 
branches  of  the  anterior  tibial  and  the  external  circumflex  of  the  profunda. 
Its  Nerves  are  derived  from  the  obturator,  anterior  crural,  external  and 
internal  popliteal.  It  has  14  ligaments,  of  which  6  are  external  and  8 
internal,  as  follows: — 

Anterior,  or  Ligamentum  Patella, — is  the  central  portion  of  the  common 
tendon  of  the  extensor  muscles  of  the  thigh,  continued  from  the  patella 
to  the  tubercle  of  the  tibia  (9,  Fig.  41). 


HUMAN    ANATOMY 


Posterior,  the  oblique  portion  of  which  is  often  called  Ligamentum 
Winslowii  (i), — from  the  upper  margin  of  the  intercondyloid  notch 
of  the  femur  to  the  posterior  margin  of  the  head  of  the  tibia,  being 
pIG.  4o.  partly  derived  from  the  tendon  of  the  semi- 

membranosus  muscle  (2): 

Internal  Lateral  (1.  collateral  tibiale)  (5), — from 
the  internal  condyle  of  the  femur  to  the  inner 
tuberosity  of  the  tibia  and  the  internal  semi- 
lunar  cartilage. 

External  Lateral  2, — from  the  external  condyle 
of  the  femur  to  the  head  of  the  fibula. 
These  ligaments  are  a  Long  (1.  collaterale 
fibulare)  (6)  is  a  divorced  portion  of  the 
peroneus  longus  muscle.  The  short  external 
lateral  ligament  (1.  laterale  externum  breve 
seu  posticum)  (7)  is  often  wanting,  when 
present,  it  is  behind  the  long  external  lateral 
and  separated  from  it  by  the  tendon  of  the 
biceps. 

Capsular, — is  a  thin  but  very  strong  membrane,  which  fills  in  the 
intervals  left  between  the  preceding  ligaments  and  is  inseparably 
connected  with  them. 
The  Internal  Ligaments  are  as  follows: — 

Anterior  Crucial  (2), — from  the  depression  in 
front  of  the  spine  of  the  tibia  to  the  inner  side 
of  the  outer  condyle  of  the  femur. 
Posterior  Crucial  (3), — from  the  depression  behind 
the  spine  of  the  tibia  and  the  popliteal  notch,  to 
the  outer  side  of  the  inner  condyle  of  the  femur. 
[To  remember  the  positions  and  insertions  of 
these  crucial  ligaments,  let  the  student  cross 
his  index  fingers  over  each  knee  in  succession; 
when  over  the  right  knee  placing  the  right 
finger  in  front,  when  over  the  left  knee  the 
left  finger  in  front.  The  positions  of  the  fingers 
will  in  each  case  correspond  with  those  of  the 
respective  crucial  ligaments.] 

Semilunar  Fibro-cartilages  (menisci)  2, — external  (7)  and  internal  (6), 
are  situated  between  the  articular  surfaces,  and  attached  to  the 
depressions  in  front  and  behind  the  spine  of  the  tibia.  The  external 
one  forms  nearly  an  entire  circle  and  gives  off  posteriorly  a  strong 


PIG.  41. 


ARTICULATIONS    OF   LOWER   EXTREMITY  71 

fasciculus,  the  ligament  of  Wrisberg,  which  is  inserted  into  the  inner 

condyle  of  the  femur. 
Transverse  (4), — is  a  connecting  slip  between  the  semilunar  fibro-carti- 

lages  anteriorly. 
Coronary  or  Coronal  (7), — are  short  bands  connecting  the  outer  margins 

of  the  fibro-cartilages  with  the  margin  of  the  head  of  the  tibia. 
Ligamenium  Mucosum  (plica  synovialis  patellaris) , — is  a  triangular  fold 

of  the  synovial  membrane  which  at  the  lower  border  of  the  patella  is 

given  off  to  the  intercondylar  notch  of  the  femur. 
Ligamenta  Alaria  (plicae  alares), — are  two  fringe-like  folds  on  the  sides 

of  the  ligamentum  mucosum,  and  are  attached  to  the  semilunar 

cartilages. 
Bursa, — in  the  vicinity  of  this  joint  are  1 2  in  number;  3  in  front,  4  on  the 

outer  side,  and  5  on  the  inner  side.     Some  of  these  are  expansions 

from  others,  some  often  communicate  with  the  joint,  and  some  are 

only  occasionally  present.     That  between  the  patella  and  the  skin  is 

the  one  implicated  in  the  affection  called  "house-maid's  knee." 

The  Tibio-fibular  Articulations  are  3  in  number,  as  follows,  viz. — 

SUPERIOR  TIBIO-FIBULAR  ARTICULATION,  in  an  arthrodial  joint,  formed 
by  the  contiguous  surfaces  of  the  bones.  It  has  a  Synovial  Membrane 
which  is  sometimes  continuous  with  that  of  the  knee-joint,  and  3  liga- 
ments, the — 

Capsular, — a  membranous  bag  surrounding  the  joint  and  much  thicker 
in  front  than  behind. 

Anterior  and  Posterior  Superior  Tibio-fibular  (10), — which  connect  the 
head  of  the  fibula  with  the  outer  tuberosity  of  the  tibia. 

MIDDLE  TIBIO-FIBULAR  ARTICULATION.  The  shafts  of  these  bones  do 
not  touch  each  other,  but  are  connected  by  an  Interosseous  Membrane 
extending  between  their  contiguous  borders,  and  perforated,  above  for  the 
anterior  tibial  vessels,  below  for  the  anterior  peroneal  vessels. 

INFERIOR  TIBIO-FIBULAR  ARTICULATION,  is  an  amphiarthrodial  joint,  of 
the  subdivision  syndesmosis,  and  is  formed  by  the  contiguous  rough 
surfaces  on  the  lower  ends  of  these  bones.  Its  Synovial  Membrane  is 
derived  from  that  of  the  ankle-joint,  and  it  has  4  ligaments,  the — 

Inferior  Interosseous, — continuous  with  the  interosseous  membrane. 

Anterior  and  Posterior  Inferior  Tibio-fibular, — from  the  margins  of  the  ex- 
ternal malleous  to  the  front  and  back  of  the  tibia. 

Transverse, — posteriorly  between  the  2  malleoli. 

The  Ankle-joint  is  a  ginglymus  or  hinge-joint  articulation,  formed  by  the 
lower  ends  of  the  tibia  and  fibula  and  their  malleoli,  with  the  astragalus. 


72  HUMAN   ANATOMY 

Its  Synovial  Membrane  is  prolonged  upward  between  the  tibia  and  fibula  for 
a  short  distance.  Its  Arteries  are  derived  from  the  malleolar  branches  of 
the  anterior  tibial  and  peroneal  arteries;  and  its  Nerves  from  the  anterior 
and  posterior  tibial  nerves.  It  has  4  ligaments;  the — 

Anterior, — connecting  the  anterior  margins  of  the  tibia  and  astragalus 

or  talus. 
Posterior, — a  very  thin  band  of  transverse  fibres,  connecting  the  posterior 

margins  of  the  tibia  and  astragalus. 
Internal  Lateral  or  Deltoid  Ligament   (1.    calcaneotibiale) , — from   the 

internal  malleolus  to  the  3  adjacent  tarsal  bones. 

External  Lateral, — by  anterior  (1.  talofibulare  anterius),  posterior  (1. 
talofibulare  posterius)  and  middle  (1.  calcaneofibulare)  fasciculi,  from 
the  external  malleolus  to  the  astragalus  and  os  calcis. 

The  Tarsal  Articulations  are  connected  by  the  following-named  liga- 
ments, viz.,  the — 

Calcaneo-astragaloid  3,  external,  internal  and  posterior, — connecting  the 

os  calcis  with  the  astragalus. 
Calcaneo-cuboid  4,  superior,  internal,  long  and  short, — connecting  the 

os  calcis  with  the  cuboid. 
Calcaneo-navicular  2,  superior  and  inferior, — connecting  the  os  calcis 

with  the  scaphoid  or  navicular  bone. 
Astragalo-navicular,    superior, — connecting    the    astragalus    with    the 

scaphoid  or  navicular  bone. 
Dorsal  and  Plantar  Ligaments, — connecting  the  scaphoid  with  the  three 

cuneiform  and  with  the  cuboid,  the  three  cuneiform  with  each  other, 

and  the  external  cuneiform  with  the  cuboid. 
Interosseous  Ligaments, — connecting  the  os  calcis  with  the  astragalus, 

the  scaphoid  with  the  cuboid,  the  cuneiform  bones  with  each  other, 

and  the  external  cuneiform  with  the  cuboid. 
Nerves.     All  the  joints  of  the  tarsus  are  supplied  by  the  anterior  tibial 

nerve. 

The  Tarso-metatarsal  Articulations  are  5  arthrodial  joints  formed  by 
the  bases  of  the  metatarsal  bones  with  the  adjacent  bones  of  the  tarsus,  the 
2d  metatarsal  bone  articulating  with  all  3  cuneiform  in  the  recess  formed 
by  the  shortness  of  the  second  cuneiform.  They  are  united  by  Dorsal, 
Plantar,  and  3  Interosseous  Ligaments.  The  2d  metatarsal  bone  has  3 
dorsal  ligaments,  i  from  each  cuneiform  bone.  The  interosseous  ligaments 
pass  from  the  2d  and  3d  metatarsal  bones  to  the  internal  and  external 
cuneiform. 


MUSCLES    AND    FASCIA  73 

Synovial  Membranes  of  the  Tarsus  and  Metatarsus  are  6  in  number, 
and  are  situated  as  follows,  viz. — 
First, — between  the  os  calcis  and  the  astra'galus,  behind  the  interosseous 

ligament. 
Second, — between  the  same  bones  in  front  of  the  interosseous  ligament, 

also  between  the  astragalus  and  the  scaphoid. 
Third, — between  the  os  calcis  and  the  cuboid. 

Fourth, — between  the  scaphoid  and  the  3  cuneiform  bones,  running  back- 
ward between  the  scaphoid  and  the  cuboid,  forward  between  the 
cuneiform  bones,  between  the  external  cuneiform  and  the  cuboid, 
between  the  middle  and  external  cuneiform  and  the  bases  of  the  2d 
and  3d  metatarsal,  passing  also  between  the  bases  of  these  bones  and 
the  4th  metatarsal. 
Fifth, — between  the  internal  cuneiform  and  the  base  of  the  ist  metatarsal 

bone. 
Sixth, — between  the  cuboid  and  the  4th  and  5th  metatarsal  bones,  also 

running  forward  between  their  bases. 

The  Metatarso -metatarsal  Articulations.  The  metatarsal  bones  are 
connected  together,  except  the  first,  at  their  bases  by  Dorsal,  Plantar,  and 
Interosseous  Ligaments.  The  base  of  the  first  metatarsal  is  not  connected 
with  the  base  of  the  second  by  any  ligaments,  resembling  the  thumb  in  this 
respect. 

Remaining  Articulations  of  the  Foot.  The  metatarso-phalangeal 
and  the  phalangeal  articulations  are  similar  to  those  in  the  hand,  each 
having  a  Plantar  and  2  Lateral  Ligaments.  The  extensor  tendons  supply 
the  places  of  the  posterior  ligaments. 

THE  MUSCLES  AND  FASCLE 

The  Muscles  are  the  active  organs  of  locomotion,  formed  of  bundles  ol 
reddish  fibres  endowed  with  the  property  of  shortening  themselves  upon 
irritation,  which  is  called  muscular  contractility,  and  chemically  consisting 
of  75  per  cent,  of  water,  20  of  proteids,  2  of  fat,  i  of  nitrogenous  extractives 
and  carbohydrates,  and  2  per  cent,  of  salts,  mainly  potassium  phosphate 
and  carbonate. 

The  Muscles  are  divided  into  2  great  classes, — Voluntary,  Striped,  or 
Muscles  of  animal  life,  comprise  those  which  are  under  the  control  of  the 
will.  Involuntary,  Unstriped,  or  Muscles  of  organic  life,  are  those  which 
are  not  under  the  control  of  the  will. 

Voluntary  Muscular  Fibre  consists  of  fasciculi  enclosed  in  a  delicate 
web,  the  perimysium,  connected  together  by  a  delicate  connective  tissue, 


74  HUMAN    ANATOMY 

the  endomysium,  aggregated  into  muscular  fibres,  from  ^Oo  inch  to  ^oo 
inch  in  diameter,  which  are  enclosed  in  tubular  sheaths,  the  sarcolemma, 
and  are  marked  by  fine  stria  *passing  around  them  transversely  or  some- 
what obliquely.  The  fasciculi  are  formed  of  longitudinal  fibrillae  or 
sarcostyles,  made  up  of  successive  portions  called  sarcomeres,  each  of  which 
consists  of  a  central  dark  part  the  sarcous  element,  and  a  clear  layer  which 
is  most  visible  when  the  fibre  is  extended  (Schafer). 

Involuntary  Muscular  Fibre  is  made  up  of  spindle-shaped  cells,  the 
contractile  fibre-cells,  averaging  ^50  inch  long  and  ^40  oo  inch  broad,  col- 
lected into  bundles  and  held  together  by  a  cement-like  substance.  These 
are  aggregated  into  larger  bundles  or  flattened  bands,  bound  together  by 
ordinary  connective  tissue.  Involuntary  muscular  fibres  are  found  in  the 
walls  of  the  alimentary  canal,  in  the  posterior  wall  of  the  trachea,  in  the 
bronchi,  the  ducts  of  certain  glands,  in  the  ureters,  bladder,  urethra, 
genitalia  of  both  sexes,  walls  of  all  arteries  and  most  veins  and  lymphatics, 
in  the  iris  and  ciliary  muscle,  and  in  the  skin. 

*j£  7  Tendons  and  Aponeuroses.     Tendons  are  white,  glistening  cords  or 

'     bands  formed  of  white  fibrous  tissue  almost  entirely,  have  few  vessels  and 

no  nerves  in  the  smaller  ones.     They  serve  to  connect  the  muscles  with 

the  structures  on  which  they  act.     Aponeuroses  are  fibrous  membranes, 

of  similar  structure  and  appearance,  and  serve  the  same  purpose. 

Fasciae  are  laminae  of  variable  thickness  which  invest  (fascia,  a  bandage) 
the  softer  structures.  The  superficial  fascia  or  subcutaneous  tela  consists 
of  two  layers,  a  superficial  fatty  layer  (panniculus  adiposus)  which  is 
closely  adherent  to  the  true  skin,  covering  over  almost  the  entire  body. 
Except  on  the  eyelids,  penis,  and  scrotum,  it  contains  much  fat.  The 
deep  layer  of  the  superficial  fascia  is  a  fibro-muscular  layer  (panniculus 
carnosus)  it  envelops  the  entire  trunk.  On  the  sides  of  the  neck  and  upper 
part  of  the  chest  it  is  muscular  and  is  there  called  the  platysma,  it  is  also 
muscular  in  the  scrotum  where  it  is  called  the  dartos.  The  deep  fascia 
is  of  aponeurotic  structure,  dense,  inelastic,  and  fibrous,  ensheathing  the 
muscles  and  affording  some  of  them  attachment,  it  also  forms  the  sheaths 
of  the  vessels  and  nerves,  and  binding  down  the  whole  into  a  shapely  mass. 

Muscles  are  attached  to  the  periosteum  and  perichondrium  of  bone  and 
cartilage,  to  the  subcutaneous  areolar  tissue,  and  to  ligaments.  In  the 
latter  case  only  are  their  tendons  in  direct  contact  with  the  tissue  on  which 
they  are  to  act. 

Double-bellied  Muscles  are  4  in  number,  the — occipito-frontalis, 
digastric,  omo-hyoid,  and  the  diaphragm. 


MUSCLES    OF    THE   HEAD  75 

MUSCLES  OF  THE  HEAD 

CRANIAL  REGION 

Occipito-frontalis  (a) ,  arises/row  the  external  two-thirds  of  the  superior 
curved  line  of  the  occipital  bone  and  the  mastoid  process  of  the  temporal; 
also  from  the  pyramidalis  nasi,  corrugator  supercilii,  and  orbicularis  pal- 
pebrarum  fibres;  and  is  inserted  into  an  aponeurosis  or  "galea  capitis," 
which  covers  the  vertex  of  the  skull.  Action,  chiefly  as  a  muscle  of  facial 
expression.  Nerves,  the  frontal  portion  (m.  frontalis)  by  the  facial  nerve, 
the  occipital  portion  (m.  occipitalis)  by  the  posterior  auricular  branch 
of  the  facial. 

AURICULAR  REGION 

I  Auricularis  anterior,  or  Attrahens  Auriculam,— from  the  lateral  cranial 
aponeurosis:  into  the  helix  of  the  ear  anteriorly.  Action,  to  draw  the 
pinna  forward.  Nerve,  temporal  branch  of  the  facial. 

?  Auricularis  superior,  or  Attollens  Auriculam,— -from  the  occipito-frontalis 
aponeurosis:  into  thejginna  of  the  ear  superiorly.  Action,  to  raise  the 
pinna.  Nerve,  temporal  branch  of  the  facial. 

Auricularis  posterior,  or  Retrahens  Auriculam, — from  the  mastoid  process 
of  the  temporal  bone:  into  the  concha.  Action,  to  retract  the  pinna. 
Nerve,  posterior  auricular  branch  of  the  facial. 

PALPEBRAL  REGION 

Orbicularis  Palpebrarum  (m.  orbicularis  oculi), — from  the  internal 
angular  process  of  the  irontal  bone,  the  nasal  process  of  the  superior 
maxillary,  and  the  borders  of  the  tendo  oculi;  into  the  skin  of  the 
eyelids,  forehead,  temple,  and  cheek,  blending  with  the  occipito-frontalis 
and  the  corrugator  supercilii.  Action,  to  close  the  eyelids.  Nerve, 
facial;  perhaps  also  the  3d  nerve. 

Corrugator  Supercilii,— /row  the  inner  end  of  the  superciliary  ridge  of  the 
frontal  bone:  into  the  orbicularis  palpebrarum.  Action,  to  draw  eye- 
brow downward  and  inward.  Nerve,  facial;  perhaps  by  the  3d  nerve. 

Tensor  Tarsi  (is  classed  by  some  as  a  portion  (pars  lacrimalis)  of  the 
orbicularis)  it  arises, — from  the  crest  of  the  lacrimal  bone  into  the 
tarsal  cartilages  by  two  slips.  Action,  to  compress  the  puncta  lacri- 
malia  against  the  globe  of  the  eye  and  to  compress  the  lacrimal  sac. 
Nerve,  facial;  perhaps  also  the  3d  nerve. 


70  HUMAN    ANATOMY 

ORBITAL  REGION 

Levator  Palpebrae  Superioris  (9),— from  the  lesser  wing  of  the  sphenoid: 

into  the  upper  tarsal  cartilage.     Action,  to  lift  the  upper  lid.     Nerve, 

3d  cranial,  or  motor  oculi. 
The  fibrous  ring   (annulus  tendineus  communis)   from   which  arise  the 

recti  oculi  muscles,  is  divisible  into  an  upper  common  tendon  and  a 

lower  common  tendon. 

Rectus  Superior  (5), — from  the  superior  common  tendon  (ligament  of 
Lock  wood) :  into  the  sclerotic  coat.  Action,  to  rotate  the  eyeball  upward. 
Nerve,  3d  cranial. 

Rectus  Inferior  (4), — from  the  inferior  common  tendon  (ligament  of  Zinn) : 
•c.  into  the  sclerotic  coat.     Ac- 

f  Itj.     42. 

lion,  to  rotate  the  eyeball 
downward.  Nerve,  3d 
cranial. 

•Rectus  Interims  (3),— from 
the  inferior  common  ten- 
don (ligament  of  Zinn) :  into 
the  sclerotic  coat.  Action, 
to  rotate  the  eyeball  in- 
ward. Nerve,  3d  cranial. 
Rectus  Externus  (or  lateralis) 
(2), — by  2  heads,  the  upper 
from  the  superior  common 
tendon  (ligament  of  Lock- 
wood),  the  lower  from  the 
inferior  common  tendon 
(ligament  of  Zinn)  and  a 

bony  process  at  lower  margin  of  the  sphenoidal  fissure:  into  the  scle- 
rotic coat.     Action,  to  rotate  the  eyeball  outward.     Nerve,  6th  cranial, 
or  abducens. 
Between  the  2  heads  of  the  external  rectus  pass  the  3d,  nasal  branch  of  the 

5th,  and  6th  cranial  nerves,  and  the  ophthalmic  vein. 
Obliquus  Oculi  Superior  (6),— from  about  a  line  above  the  inner  margin 
of  the  optic  foramen,  its  tendon  passing  through  a  pulley  (7)  near  the 
internal  angular  process  of  the  frontal  bone  and  thence  beneath  the 
rectus  superior:  into  the  sclerotic  coat  at  right  angles  to  the  insertion  of 
the  rectus  superior.  Action,  to  rotate  the  eyeball  on  its  antero-posterior 
axis.  Nerve,  4th  cranial,  or  patheticus. 


MUSCLES    OF    THE   HEAD 


77 


FIG.  43. 


Obliquus  Oculi  Inferior  (S),—from  the  orbital  plate  of  the  maxilla:  into 
the  sclerotic  coat  below  the  insertion  of  the  external  rectus  and  at 
right  angles  thereto.  Action,  to  rotate  the  eye  on  its  antero-posterior 
axis.  Nerve,  30!  cranial. 

NASAL  REGION 

Pyramidalis  Nasi   (m.   procerus)    (c), — from  the  occipito-frontalis:  into 

the  compressor  naris.     Action,  to  depress  the  eyebrow.     Nerve,  facial. 
Levator  Labii    Superioris  Alaeque  Nasi    (caput  angulare  of   the   m. 

quadratus  labii  superioris)  (e), — from  the  nasal  process  of  the  maxilla 

bone:  into  the  cartilage  of  the  ala  of  the  nose  and  into  the  upper  lip. 

Action,  to  elevate  the  upper  lip,  and  dilate  the  nostril.     Nerve,  facial. 
Dilator  Naris  Anterior, — from  the  car- 
tilage of  the  ala:  into  the  border  of 

its    integument.     Action,    to    dilate 

the  nostril.     Nerve,  facial. 
Dilator     Naris    Posterior, — from    the 

nasal  notch  of  the  maxilla  and  the 

sesamoid  cartilages:  into  the  integu- 
ment a,t  the  margin  of  the  nostril. 

Action,  to  dilate  the  nostril.     Nerve, 

facial. 
Compressor  Nasi   (m.   nasalis)    (</), — 

from  the   maxilla  above  the  incisive 

fossa:  into  the  fibro-cartilage  of  the 

nose,  being  continuous  with  its  fellow 

and    the   pyramidalis  nasi  aponeu- 

rosis.     Action,  to  dilate  the  nostril. 

Nerve,  facial. 
Compressor      Narium     Minor,—; from 

the  alar  cartilage:  into  the  skin  at  the  end  of  the  nose. 

dilate  the  nostril.     Nerve,  facial. 
Depressor  Alae  Nasi  (m.  depressor    septi), — from  the  incisive   fossa   of 

the  maxilla:  into  the  septum  and  ala  of  the  nose.     Action,  to  contract 

the  nostril.     Nerve,  facial. 

MAXILLARY  REGION 

Levator  Labii  Superioris  (caput  infra-orbitale  of  the  m.  quadratus  labii 
superioris)  (/), — from  the  lower  margin  of  the  orbit:  into  the  upper 
lip.  Action,  to  elevate  the  lip.  Nerve,  facial. 


Action,  to 


78  HUMAN    ANATOMY 

LevatorAnguliOris  (m.  Caninus)  (o),—fromthe  canine  fossa  of  the  maxilla: 
into  the  angle  of  the  mouth.  Action,  as  named.  Nerve,  facial. 

Zygomaticus  Major  (m.  zygomaticus)  (h),—from  the  malar  bone:  into 
the  angle  of  the  mouth.  Action,  to  raise  the  lip  outward.  Nerve, 
facial. 

Zygomaticus  Minor  (caput  zygomaticum  of  the  m.  quadratus  labii 
superioris)  (g), — from  the  malar  bone  anteriorly:  into  the  angle  of  the 
mouth,  blending  with  the  levator  labii  superioris.  Action,  to  raise 
the  lip  outward.  Nerve,  facial. 

Musculus  Quadratus  Labii  Superioris  (B.  N.  A.)  comprises  three  muscles, 
each  one  of  which  is  called  a  head  or  caput.  The  three  heads  are  called 
respectively,  caput  angiilare,  caput  infra-orbitale,  and  caput  zygo- 
maticum. The  regular  names  for  these  three  heads,  are,  in  the  order 
given,  levator  labii  superioris  alaequae  nasi,  levator  labii  superioris, 
and  zygomaticus  minor. 

MANDIBULAR  REGION 

Levator  Menti  (m.  mentalis)  (m), — from  the  incisive  fossa  of  the  mandible 

bone:  into  the  integument  of  the  chin.     Action,   as  named.     Nerve, 

facial. 
Depressor  Labii  Inferioris  (m.  quadratus  labii  inferioris)  (I),— from  the 

external  oblique  line  of  the  mandible:  into  the  lower  lip.     Action,  as 

named.     Nerve,  facial. 
Depressor  Anguli  Oris  (m.  triangularis)  (»), — from  the  external  oblique 

line  of  the  mandible:  into  the  angle  of  the  mouth.     Action,  as  named. 

Nerve,  facial. 

BUCCAL  REGION 

Orbicularis  Oris  (&), — is  the  sphincter  of  the  lips,  the  upper  portion,  in 
the  upper  lip,  is  attached  in  the  mid-line  to  the  septum  of  the  nose 
(naso-labial  band),  laterally  it  is  attached  to  the  incisor  fossa  of  the 
maxilla  (superior  incisive  bundle).  The  lower  portion,  in  the  lower 
lip,  is  attached  to  the  mandible  immediately  above  the  mental  pro- 
tuberance (inferior  incisive  bundle).  At  the  corner  of  the  mouth, 
the  upper  and  lower  portions  decussate  with  each  other  and,  deeply, 
with  the  buccinator.  Action,  to  close  the  mouth.  Nerve,  facial. 

Buccinator  (j),—from  the  alveolar  arches  of  both  the  maxillae  and  mandible 
and  from  the  pterygo-mandibular  ligament:  into  the  orbicularis  oris. 
It  forms  the  lateral  walls  of  the  mouth;  it  is  pierced  by  the  parotid  duct. 


MUSCLES    OF    THE    EAR  79 

Action,  to  compress  the  cheeks.     Nerves  (motor)  facial,  and  (sensory) 
the  long  buccal  branch  of  the  mandibular. 

Risorius, — from  the  fascia  over  the  masseter  muscle:  into  the  angle  of  the 
mouth.  Action,  the  laughing  muscle.  Nerve,  facial. 

TEMPORO-MANDIBULAR  REGION 

Masseter  (i), — from  the  anterior  two-thirds  and  the  inner  surface  of  the 
zygoma  and  the  malar  process  of  the  maxilla:  into  almost  all  of  the  outer 
surface  of  the  angle,  ramus,  and  coronoid  process  of  the  lower  jaw. 
A ction,  to  raise  the  back  part  of  the  lower  jaw;  a  muscle  of  mastication. 
Nerve,  masticator  portion  of  mandibular. 

Temporal,— from  the  temporal  fossa  and  temporal  fascia:  into  the  coronoid 
process  of  the  mandible.  Action,  to  bring  the  incisor  teeth  together; 
the  biting  muscle.  Nerve,  masticator  portion  of  mandibular. 

PTERYGO-MANDIBULAR  REGION 

External  Pterygoid, — by  2  heads,  the  upper,  from  the  pterygoid  ridge  on 
the  greater  wing  of  the  sphenoid,  the  lower  from  the  external  pterygoid 
plate,  and  the  tuberosities  of  the  palate  and  maxilla:  into  a  depression  in 
front  of  the  condyle  of  the  mandible,  and  the  inter-articular  fibro- 
cartilage.  Action,  to  draw  the  jaw  forward;  a  triturating  muscle  of 
mastication.  Nerve,  masticator  portion  of  mandibular. 

Between  the  two  heads  of  the  external  pterygoid  muscle  passes  the  internal 
maxillary  artery. 

Internal  Pterygoid,— from  the  pterygoid  fossa  of  the  sphenoid  bone,  and 
the  tuberosity  of  the  palate:  into  the  angle  and  inner  surface  of  the 
ramus  of  the  jaw,  as  high  as  the  dental  foramen.  Action,  raises  and 
draws  forward  the  lower  jaw;  a  triturating  muscle  of  mastication. 
Nerve,  masticator  portion  of  mandibular. 

MUSCLES  OF  THE  EAR 

The  muscles  of  the  ear  include  those  of  the  pinna  and  those  of  the  tym- 
panum. The  former  are  divided  into  two  sets:  Extrinsic, — the  attra- 
hens,  attollens  and  retrahens  auriculam  (see  page  75);  and  the  Intrinsic,  as 
follows: — 

INTRINSIC  MUSCLES  OF  THE  PINNA 

Helicis  Major,— from  the  cauda  helicis:  into  the  anterior  border  of  the 
helix.  Nerve,  facial. 


8o  HUMAN    ANATOMY 

Helicis  Minor, — an  oblique  fasciculus  which  covers  the  crus  helicis. 
Nerve,  facial. 

Tragicus, — a  short,  vertical  band  of  muscular  fibres,  on  the  outer  surface  of 
the  tragus.  Nerve,  facial. 

Antitragicus, — from  the  antitragus:  into  the  cauda  helicis  and  antihelix. 
Nerve,  facial. 

Transversus  Auriculae, — on  the  cranial  surface  of  the  pinna,  from  the  con- 
vexity of  the  concha:  into  the  prominence  corresponding  to  the  groove  of 
the  helix.  Nerve,  facial. 

Obliquus  Auriculae. — from  the  upper  and  back  part  of  the  concha:  into  the 
convexity  immediately  above  it.  Nerve,  facial. 

MUSCLES  OF  THE  TYMPANUM 

i  Tensor  Tympani, — from  the  under  surface  of  the  petrous  portion  of  the 
temporal  bone,  the  cartilaginous  Eustachian  tube,  and  its  own  osseous 
canal:  into  the  handle  of  the  malleus.  Action,  to  draw  the  membrana 
tympani  inward  and  tense.  Nerve,  branch  from  otic  ganglion. 

Laxator  Tympani, — from  the  base  of  the  alar  spine  of  the  sphenoid,  its  ten- 
don passing  through  the  petro-tympanic  fissure  to  be  attached  to  the 
processus  gracilis  (anterior  processus)  of  the  malleus.  Nerve,  branch 
from  otic  ganglion  (see  page  301 ). 

Stapedius, — from  the  interior  of  the  pyramid,  through  the  orifice  at  its 
apex:  into  the  neck  of  the  stapes.  Action,  to  rotate  the  base  of  the 
stapes  and  compress  the  contents  of  the  vestibule.  Nerve,  tympanic 
branch  of  the  facial. 

MUSCLES  OF  THE  NECK 

SUPERIOR  CERVICAL  REGION 

/  Platysma  Myoides  (panniculus  carnosus), — is  a  muscular  fascia  covering 
the  pectoral  and  cervical  region;  it  is  loosely  attached  to  the  lower  jaw, 
the  angle  of  the  mouth,  the  skin,  and  the  cellular  tissue  of  the  face. 
Action,  to  wrinkle  the  skin,  and  depress  the  mouth.  Nerve,  facial. 

Sterno-cleido-mastoid  (n), — by  two  heads  from  the  sternum  (12)  and  the 
clavicle  (13)  at  its  inner  third:  into  the  mastoid  process  of  the  temporal 
bone,  and  the  outer  half  of  the  superior  curved  line  of  the  occipital.  Ac- 
tion, to  depress  and  rotate  the  head.  Nerves,  spinal  accessory,  and  deep 
branches  of  the  cervical  plexus. 


MUSCLES    OF    THE    NECK 


8l 


INFRA-HYOID  REGION 

Sterno-hyoid  (14), — from  the  posterior  surface  of  the  sternum  and  the 
sternal  end  of  the  clavicle:  into  the  body  of  the  hyoid  bone.  Action,  to 
depress  the  hyoid  bone.  Nerve,  a  branch  from  the  communicating  loop 
(ansa  hypoglossi)  between  the  descendens  and  communicans  hypoglossi. 

Sterno-thyroid  (m.  sterno-thyreoideus)  (i$),—from  the  posterior  surface 
of  the  sternum  and  the  cartilage  of  the  ist  rib:  into  the  oblique  line  on 
the  ala  of  the  thyroid  cartilage.  Action,  to  depress  the  thyroid  (thy- 
reoid)  cartilage.  Nerve,  a  branch  from  the  communicating  loop  (ansa 
hypoglossi)  between  the  descendens  and  communicans  hypoglossi. 

FIG.  44- 


Thyro-hyoid  (m.  thyreohyoideus)  (16), — from  the  oblique  line  on  the  thy- 
roid cartilage:  into  the  body  and  greater  cornu  of  the  hyoid  bone. 
Action,  to  depress  the  larynx  and  the  hyoid  bone.  Nerve,  hypoglossal. 

Omo-hyoid  (17,  i8),—from  the  upper  border  of  the  scapula  and  the  trans- 
verse ligament:  into  the  body  of  the  hyoid  bone.  It  has  a  tendon  in  its 
centre  which  is  bound  down  to  the  clavicle  and  the  ist  rib  by  a  loop  of  the 
deep  cervical  fascia.  Action,  to  depress  the  hyoid  bone,  and  draw  it 
backward.  Nerve,  branch  from  the  communicating  loop  (ansa  hypo- 
glossi) between  the  descendens  and  communicans  hypoglossi. 
6 


82  HUMAN    ANATOMY 


SUPRA-HYOID  REGION 

Digastric, — by  2  bellies,  the  posterior  one  (i)  from  the  digastric  groove  of 
the  mastoid  process  of  the  temporal  bone;  the  anterior  (2)  from  a  fossa 
on  the  inner  surface  of  the  mandible  near  its  symphysis:  into  a  cen- 
.  tral  tendon  (3)  which  perforates  the  stylo-hyoid  muscle,  and  is  bound 
down  to  the  body  of  the  hyoid  bone  by  an  aponeurotic  loop.  Action,  to 
raise  the  hyoid  bone  and  tongue.  Nerves,  anterior  belly  is  supplied  by  a 
branch  of  the  mylo-hyoid  nerve,  the  posterior  belly  by  the  facial  nerve. 

Stylo-hyoid  (4),— -from  thestyloid  process  of  the  temporal  bone  near  its 
base:  into  the  body  of  the  hyoid  bone.  Action,  to  elevate  and  retract 
the  hyoid  bone.  Nerve,  facial.  This  muscle  is  perforated  by  the 
digastric. 

Mylo-hyoid  (5), — -from  the  mylo-hyoid  ridge  of  the  lower  jaw:  into  the 
body  of  the  hyoid  bone  and  a  median  fibrous  raphe  line  running  from  the 
hyoid  bone  to  the  lower  jaw.  Action,  elevates  the  hyoid  bone  and  draws 
it  forward,  also  forms  the  floor  of  the  mouth.  Nerve,  mylo-hyoid  branch 
of  inferior  dental  (inferior  alveolar). 

Genio-hyoid  (6), — from  the  inferior  genial  tubercles  (mental  spines)  of 
the  mandible  into  the  body  of  the  hyoid  bone.  Action,  same  as  that  of 
the  mylo-hyoid.  Nerve,  hypoglossal. 

LINGUAL  REGION 

Genio-hyo-glossus  (m.  genioglossus), — from  the  superior  genial  tubercles 
(mental  spines)  of  the  mandible:  into  the  body  of  the  hyoid  bone,  the 
side  of  the  pharynx,  and  the  whole  length  of  the  under  surface  of  the 
tongue,  forming  a  fan-like  muscle.  Action,  to  retract  and  protrude 
the  tongue.  Nerve,  hypoglossal. 

Hyo-glossus  (8),— from  the  side  of  the  body  of  the  hyoid  bone,  and  the 
whole  length  of  its  greater  cornu:  into  the  side  of  the  tongue.  Action,  to 
draw  down  the  side  of  the  tongue.  Nerve,  hypoglossal. 

Chondro-glossus, — sometimes  described  as  a  part  of  the  hyo-glossus,  from 
the  lesser  cornu  and  the  body  of  the  hyoid  bone:  into  the  intrinsic  mus- 
cular fibres  of  the  tongue,  between  the  hyo-glossus  and  the  genio-hyo- 
glossus.  Action,  as  the  hyo-glossus.  Nerve,  hypoglossal. 

Stylo-glossus  (9), — from  the  styloid  process  and  the  stylo-mandibular  liga- 
ment:  into  the  side  of  the  tongue  and  the  hyo-glossus  muscle.     Action, 
to  elevate  and  retract  the  tongue.     Nerve,  hypoglossal. 


MUSCLES    OF    THE   PHARYNX  83 

Palato-glossus  (m.  glossopalatinus), — is  one  of  the  muscles  of  the  tongue, 
serving  to  draw  its  base  upward,  but  is  described  with  the  muscles  of 
the  palatal  region. 

Lingualis  (the  tongue-muscle),  in  4  strata, — longitudinalis  lingua 
superior,  composed  of  fibres  passing  forward  and  outward;  stratum 
derived  principally  from  the  extrinsic  muscles,  the  stylo-glossus,  hyo- 
glossus,  etc.;  tr answer sus  lingua  and  verticalis  lingua,  the  latter 
found  only  at  the  borders  of  the  fore  part  of  the  tongue;  longitudinalis 
lingua  inferior  and  fibres  from  the  stylo-glossus.  Action,  to  give  the 
tongue  its  various  forms.  Nerve,  the  hypoglossal  is  the  motor  nerve  of 
the  tongue. 

PHARYNGEAL  REGION 

Inferior  Constrictor, — from  the  sides  of  the  cricoid  and  thyroid  cartilages 
into  the  fibrous  raphe  of  the  pharynx.  Action,  to  contract  the  pharyn- 
geal  calibre.  Nerves,  branches  from  the  pharyngeal  plexus,  external 
laryngeal,  recurrent  laryngeal. 

Middle  Constrictor,— -from  the  cornua  of  the  hyoid  bone  and  the  stylo- 
hyoid  ligament :  into  the  fibrous  pharyngeal  raphe.  Action,  to  constrict 
the  pharynx.  Nerves,  branches  from  the  pharyngeal  plexus. 

Superior  Constrictor,— from  the  lower  third  of  the  margin  of  the  internal 
pterygoid  plate  and  its  hamular  process,  the  contiguous  part  of  the 
palate  bone,  the  tendon  of  the  tensor  palati,  the  pterygo-mandibular 
ligament,  part  of  the  alveolar  process  of  the  lower  jaw  and  the  side  of  the 
tongue:  into  the  fibrous  pharyngeal  raphe  and  the  pharyngeal  spine  of 
the  occipital  bone.  Action,  to  constrict  the  pharynx.  Nerves,  branches 
from  the  pharyngeal  plexus. 

Stylo-pharyngeus  (io),—from  the  inner  side  of  the  base  of  the  styloid  proc- 
ess: into  the  constrictor  and  palato-pharyngeus  muscles,  and  the  thy- 
roid cartilage.  Action,  to  elevate  the  pharynx.  Nerve,  glosso-pharyn- 
geal  nerve  which  crosses  this  muscle  in  passing  to  the  tongue. 

PALATAL  REGION 

Levator  Palati  (m.  Levator  veli  palatini), — from  the  under  surface  of  the 
apex  of  the  petrous  portion  of  the  temporal  bone  and  from  the  Eusta- 
chian  tube:  into  the  posterior  surface  of  the  soft  palate.  Action,  to 
elevate  the  soft  palate.  Nerve,  pharyngeal  plexus. 

Tensor  Palati  (m.  tensor  veli  palatini),— 'from  the  scaphoid  fossa  and  the 
spine  of  the  sphenoid  bone  and  the  Eustachian  tube,  reflected  around 
the  hamular  process:  into  the  anterior  surface  of  the  soft  palate,  and  the 


84  HUMAN    ANATOMY 

horizontal  portion  of  the  palate  bone.  Action,  to  make  tense  the  soft 
palate.  Nerve,  a  branch  from  the  otic  ganglion. 

Azygos  Uvulae  (m.  uvulae),— from  the  posterior  nasal  spine  of  the  palate 
bone,  and  from  the  soft  palate:  into  the  uvula.  Action,  possibly  to 
raise  the  uvula.  This  muscle  is  wrongly  named,  as  it  is  a  double  muscle. 
Nerve,  pharyngeal  plexus. 

Palato-glossus  (m.  glossopalatinus)  (constrictor  isthmi  faucium), — front 
the  anterior  surface  of  the  soft  palate  on  the  side  of  the  uvula:  into  the 
side  and  dorsum  of  the  tongue.  Action,  to  constrict  the  fauces.  It 
forms  the  anterior  pillar  of  the  fauces.  Nerve,  pharyngeal  plexus  of  the 
spinal  accessory. 

Palato-pharyngeus  (m.  pharyngopalatinus)  (posterior  pillar  of  the  fauces), 
— from  the  soft  palate:  into  the  side  of  the  pharynx  and  the  posterior 
border  of  the  thyroid  cartilage,  having  joined  the  stylo-pharyngeus. 
Action,  to  close  the  posterior  nares.  Nerve,  pharyngeal  plexus. 

Salpingo-pharyngeus, — from  the  Eustachian  tube  near  its  orifice:  into  the 
posterior  fasciculus  of  the  palato-pharyngeus.  A  ction,  to  raise  the  upper 
and  lateral  part  of  the  pharynx.  Nerve,  pharyngeal  plexus. 

PREVERTEBRAL  REGION 

Rectus  Capitis  Anti'cus  Major  (m.  longus  capitis),— from  the  anterior 
tubercles  of  the  transverse  processes  of  the  3d,  4th,  5th,  and  6th  cervical 
vertebrae  by  4  slips:  into  the  basilar  process  of  the  occipital  bone.  Action, 
to  flex  and  rotate  the  head.  Nerves,  first  cervical  and  the  loop  between 
it  and  the  second.  This  muscle  seems  to  be  a  continuation  of  the 
scalenus  anticus. 

Rectus  Capitis  Anti'cus  Minor  (m.  rectus  capitis  anterior},— from  the 
anterior  surface  of  the  lateral  mass  of  the  atlas,  and  the  root  of  its  trans- 
verse process, — into  the  basilar  process  of  the  occipital  bone.  Action, 
to  flex  and  rotate  the  head.  Nerves,  as  the  rectus  capitis  anticus  major. 

Rectus  Capitis  Lateralis,— from  the  upper  surface  of  the  transverse  process 
of  the  atlas:  into  the  jugular  process  of  the  occipital  bone.  Action,  to 
draw  the  head  laterally.  Nerves,  as  the  preceding  muscles. 

Longus  Colli,  3  portions, — the  superior  oblique,  from  the  anterior  tubercles 
of  the  transverse  processes  of  the  3d,  4th,  and  5th  cervical  vertebrae,  into  a 
tubercle  on  the  anterior  arch  of  the  atlas: — inferior  oblique,  from  the 
bodies  of  the  first  2  or  3  dorsal  vertebrae,  into  the  transverse  processes  of 
the  5th  and  6th  cervical: — vertical  portion,  from  the  bodies  of  the  lower 
3  cervical  and  upper  3  thoracic  vertebrae,  to  the  bodies  of  the  2d,  3d,  and 


MUSCLES    OF   THE   LARYNX   AND   EPIGLOTTIS  85 

4th  cervical.  Action,  to  flex  and  slightly  rotate  the  cervical  portion  of 
the  spine.  Nerves,  branches  from  the  anterior  divisions  of  the  lower 
cervical  nerves. 

LATERAL  VERTEBRAL  REGION 

Scalenus  Anti'cus  (m.  scalenus  anterior)  (20),— from  the  transverse  proc- 
esses of  the  cervical  vertebrae,  from  the  3d  to  the  6th  inclusive:  into 
the  scalene  tubercle  on  the  upper  surface  of  the  ist  rib.  Action,  to 
flex  the  neck  laterally,  or  to  raise  the  ist  rib.  Nerves,  branches  from  the 
lower  cervical.  (See  Fig.  44.) 

Scalenus  Medius  (22),— -from  the  transverse  processes  of  the  lower  6  cer- 
vical vertebrae:  into  the  upper  surface  of  the  ist  rib,  behind  the  subcla- 
vian  groove.  Action,  same  as  the  scalenus  anticus.  Nerves,  branches 
from  the  lower  cervical. 

Scalenus  Posti'cus  (m.  scalenus  posterior)  (21), — from  the  posterior  tu- 
bercles on  the  transverse  processes  of  the  lower  2  or  3  cervical  vertebrae: 
into  the  outer  surface  of  the  2d  rib,  behind  the  serratus  magnus.  Action, 
to  flex  the  neck  laterally,  or  to  elevate  the.  2d  rib.  Nerves,  branches 
from  lower  cervical. 

MUSCLES  OF  THE  LARYNX  AND  EPIGLOTTIS 

MUSCLES  OF  THE  VOCAL  CORDS  AND  RIMA  GLOTTIDIS 

Crico-thyroid  (m.  cricothyreoideus),— 'from  the  front  and  side  of  thecricoid 
cartilage  (6) :  into  the  lower  and  inner  borders  of  the  thyroid  cartilage 
(c).     Action,  to  elongate  and  make  tense  the 
vocal  cords.     Nerve,  external  laryngeal. 

Crico-arytenoideus  Posticus  (posterior),—- from 
the  cricoid  cartilage  posteriorly :  into  the  outer 
angle  of  the  base  of  the  arytenoid  cartilage. 
Action,  to  rotate  the  arytenoid  cartilages  out- 
ward and  open  the  glottis,  while  keeping  the 
vocal  cords  tense.  Nerve,  recurrent  laryngeal. 

A  small  fasciculus,  called  Kerato-cricoideus,  is 
sometimes  found  below  the  arytenoideus,  ex- 
tending from  the  cricoid  cartilage  to  the  inferior 
cornu  of  the  thyroid.  It  occurs  once  in  5  cases, 
usually  on  one  side  only,  but  occasionally  on 
both,  and  acts  to  fix  the  lower  horn  of  the  thyroid 
cartilage  backward  and  downward.  [Sir  Wm. 
Turner.] 


86  HUMAN    ANATOMY 

Crico-arytenoideus  Lateralis  (d)—from  the  upper  border  of  the  cricoid 
cartilage  laterally:  into  the  outer  angle  of  the  base  of  the  arytenoid 
cartilage.  Action,  to  rotate  the  arytenoid  cartilages  inward  and  close 
the  glottis.  Nerve,  recurrent  laryngeal. 

Arytenoideus, — from  the  posterior  surface  and  outer  border  of  one  ary- 
tenoid cartilage:  into  the  corresponding  parts  of  the  opposite  cartilage. 
A  single  muscle  which  fills  the  posterior  concave  surface  of  these  carti- 
lages. Action,  by  approximating  the  arytenoids,  to  close  the  back  part 
of  the  glottis.  Nerves,  internal  and  recurrent  laryngeal. 

A  fairly  constant  muscle,  the  Arytenoideus  rectus,  is  found  beneath  the  ary- 
tenoideus,  extending  from  the  posterior  surface  of  the  arytenoid  carti- 
lage to  the  posterior  surface  of  the  cartilage  of  Santorini  [Luschka]. 
•v  Thyro-arytenoideus  (e), — from  the  receding  angle  of  the  thyroid  cartilage 
and  the  crico-thyroid  membrane:  into  the  base  and  anterior  surface  of 
the  arytenoid  cartilage.  Action,  to  shorten  and  relax  the  vocal  cords  by 
approximating  the  cartilages.  Nerve,  recurrent  laryngeal. 

MUSCLES  or  THE  EPIGLOTTIS 

Thyro-epiglottideus, — from  the  inner  surface  of  the  thyroid  cartilage: 
into  the  margin  of  the  epiglottis  and  the  aryteno-epiglottidean  fold. 
Action,  a  depressor  of  the  epiglottis.  Nerve,  recurrent  laryngeal. 

Aryteno-epiglottideus  Superior,— from  the  apex  of  the  arytenoid  carti- 
lage :  into  the  aryteno-epiglottidean  folds.  A  ction,  to  constrict  the  supe- 
rior laryngeal  aperture.  Nerve,  recurrent  laryngeal. 

Aryteno-epiglottideus  Inferior, — from  the  arytenoid  cartilage  anteriorly: 
into  the  anterior  surface  of  the  epiglottis.  Action,  to  compress  the 
sacculus  laryngis.  Nerve,  recurrent  laryngeal. 

Another  small  muscle  is  frequently  found,  though  rarely  described  in  the 
books,  the  Triticeo-glossus.  It  arises  from  the  cartilaginous  nodule  in 
the  posterior  thyro-hyoid  ligament,  and  passes  forward  and  upward  to 
enter  the  tongue  along  with  the  hyo-glossus  muscle.  [Bochdalek,  jun.] 

MUSCLES  OF  THE  TRUNK 

The  muscles  of  the  trunk  may  be  arranged  in  four  groups,  corresponding 
to  the  regions  in  which  they  are  situated,  viz. — those  of  the  Back,  the 
Thorax,  the  Abdomen,  and  the  Perineum. 

MUSCLES  OF  THE  BACK 

The  muscles  of  the  back  are  in  seven  layers;  these  muscles  can  be 
divided  into  two  groups.  First,  those  that  are  appsndicular,  i.e,,  those 


MUSCLES    OF    THE  BACK  87 

that  actuate  the  upper  extremity,  and  second,  those  that  are  axial,  i.e., 
those  that  act  on  the  pelvis,  ribs,  vertebrae,  and  skull. 

The  First  or  Appendicular  Group  constitutes  the  first  two  layers  of  the 
muscles  of  the  back. 
FIRST  LAYER, — 

Trapezius,  and  Latissimus  Dorsi. 
SECOND  LAYER, — 

Levator  Anguli  Scapula  (m.  leva  tor  scapulas). 

Rhomboideus  Minor. 

Rhomboideus  Major. 
The,  Second  or  Axial  Group  includes  the  remaining  five  layers,  two  that 

are  superficial  and  three  that  are  covered  in  and  surrounded  by  the 

lumbo-dorsal  fascia  (vertebral  aponeurosis). 
THIRD  LAYER, — 

Serratus  Posticus  Superior  (m.  serratus  posterior  superior). 

Serratus  Posticus  Inferior  (m.  serratus  posterior  inferior). 
FOURTH  LAYER, — 

Splenius  Capitis. 

Splenius  Cervicis  (splenius  colli). 

LUMBO-DORSAL  FASCIA  OR  VERTEBRAL  APONEUROSIS 

FIFTH  LAYER, — consists  of   two  distinct   muscular  masses,   the  sacro- 

spinal  mass  and  the  semi-spinal  mass  both  of  which  used  to  be  in- 
cluded by  the  term  erector  spinae  mass. 

The  Sacrospinal  Mass  divides  into  three  longitudinal  bundles. 
OUTER  OR  ILIO-COSTAL  DIVISION, — 

Ilio-costalis  Lumborum  (ilio-costalis  or  sacro-lumbalis). 

Ilio-costalis  Dorsi  (accessorius  ad  ilio-costalem). 

Ilio-costalis  Cervicis  (cervicalis  ascendens). 
MIDDLE  OR  LONGISSIMUS  DIVISION, — 

Longissimus  Dorsi. 

Longissimus  Cervicis  (trans versalis  colli). 

Longissimus  Capitis  (trachelo-mastoid). 
INNER  OR  SPINAL  DIVISION, — 

Spinalis  Dorsi. 

Spinalis  Cervicis  (spinalis  colli). 
THE  SEMI-SPINAL  MASS, — 

Semi-spinalis  Dorsi. 

Semi-spinalis  Cervicis  (semi-spinalis  colli). 

Semi-spinalis  Capitis   (complexus,   the  inner  portion  of   which   was 
sometimes  called  the  biventer  cervicis). 


88  HUMAN    ANATOMY 

SIXTH  LAYER, — 

Multifidus  SpincB  (m.  multifidus). 
Rotatores  Spincz  (mm.  rotatores). 
SEVENTH  LAYER, — 
Inter- spin  ales. 
Inter-transversalss  (mm.  inter-transversarii). 

THE  SUB-OCCIPITAL  MUSCLES 

Rectus  Capitis  Posticus  Major  (m.  rectus  capitis  posterior  major). 
Rectus  Capitis  Posticus  Minor  (m.  rectus  capitis  posterior  minor). 
Obliquus  Capitis  Inferior. 
Obliquus  Capitis  Superior. 
Rectus  Capitis  Lateralis. 

FIRST  LAYER 

Trapezius  (i),-^ro^the  inner  third  of  the  superior  curved  line  of  the  oc- 
cipital bone,  theligamentum  nuchae  (2),  the  spinous  processes  of  the  last 
cervical  and  all  the  thoracic  vertebrae,  and  the  supra-spinous  ligament : 
into  the  outer  third  of  the  posterior  border  of  the  clavicle,  the  superior 
margin  of  the  acromion  process,  the  whole  length  of  the  superior  border 
of  the  spine  of  the  scapula  (3),  and  a  tubercle  at  its  inner  extremity. 
Action,  to  draw  the  head  backward.  Nerves,  spinal  accessory  (n. 
accessorius) ,  cervical  plexus. 

Lie  AMENTUM  NUCHAE  (2),— from  the  external  occipital  protuberance:  to 
the  spines  of  the  cervical  vertebrae,  from  the  2d  to  the  yth  inclusive. 

Latissimus  Dorsi  (4), — by  an  aponeurosis  from  the  spines  of  the  6  lower 
thoracic  and  the  lumbar  and  sacral  vertebrae,  the  supra-spinous  ligament, 
the  crest  of  the  ilium  and  the  lower  3  or  4  ribs:  into  the  bicipital  groove  of 
the  humerus.  A  ction,  the  cursor  ani  muscle,  drawing  the  arm  downward 
and  backward;  or  raising  the  lower  ribs  and  drawing  the  trunk  forward. 
Nerve,  the  middle  or  long  subscapular. 

SECOND  LAYER. 

Levator  Anguli  Scapulae  (m.  levator  scapulae)  (10), — by  4  slips  from  the 
transverse  processes  of  the  atlas  and  3  upper  cervical  vertebrae:  into  the 
vertebra^  border  of  the  scapula.  Action,  as  named.  Nerves,  branches 
from  the  anterior  divisions  of  the  3d,  4th  and  5th  cervical  nerves. 

Rhomboideus  Minor  (n), — from  the  ligamentum  nuchae  (2)  and  spines  of 
the  7th  cervical  and  ist  thoracic  vertebrae:  into  the  smooth  surface  at 
the  root  of  the  spine  of  the  scapula.  Action,  to  draw  the  scapula  back- 


MUSCLES    OF    THE   BACK  89 

ward  and  upward.     Nerve,  branches  from  the  anterior  division  of  the 
5th  cervical. 

Rhomboideus  Major  (12), — from  the  spines  of  the  upper  4  or  5  thoracic 
vertebrae  and  the  supra-spinous  ligament :  into  the  scapula  at  the  root  of 

FIG    46. 


its  spine  and  inferior  angle,  by  a  tendinous  arch.  Action,  to  draw  the 
scapula  upward  and  backward.  Nerve,  anterior  division  of  the  5th 
cervical. 

THIRD  LAYER 

Serratus  Posti'cus  Superior  (m.  serratus  posterior  superior) ,— from  the 
ligamentum  nuchae  (a),  and  spines  of  the  yth  cervical  and  upper  2  or  3 


90  HUMAN    ANATOMY 

thoracic  vertebrae:  into  the  upper  borders  of  the  2d,  36,  4th,  and  5th 
ribs,  by  4  digitations.  A  ction,  to  raise  these  ribs  in  inspiration.  Nerves, 
external  posterior  branches  of  the  upper  thoracic  nerves. 

Serratus  Posti'cus  Inferior  (m.  serratus  posterior  inferior)  (i6)—from 
the  spines  of  the  last  2  thoracic  and  first  3  lumbar  vertebrae:  into  the 
lower  borders  of  the  lower  4  ribs,  by  4  digitations.  Action,  to  depress 
these  ribs  in  expiration.  Nerves,  external  posterior  branches  of  the 
lower  thoracic  nerves. 

FOURTH  LAYER 

Splenius  (Capitis  et  Cervicis)  (14), — from  the  lower  half  of  the  ligamentum 
nuchae  (2),  the  last  cervical  and  upper  6  thoracic  spines,  and  the  supra- 
spinous  ligament:  the  S.  capitis  (13)  into  the  mastoid  process  of  the 
temporal  bone  and  a  rough  surface  below  the  superior  nuchal 
line  of  the  occipital  bone, — the  5.  cervicis  or  colli  (14)  into  the  transverse 
processes  of  the  upper  2  or  3  cervical  vertebrae.  Action,  to  draw  the 
head  backward  and  the  neck  erect.  Nerves,  external  posterior  branches 
of  the  cervical  nerves. 

Lumbo-dorsal  Fascia  or  Vertebral  Aponeurosis, — consists  of  three  layers. 
Posterior  layer  is  the  most  extensive,  it  is  attached  to  the  spines  of 
sacral,  lumbar,  and  thoracic  vertebrae,  its  fibres  pass  out  laterally  to 
blend  in  the  lumbar  region  first  with  the  middle  layer  and  further  out,  at 
the  origin  of  the  transversalis  abdominis,  it  blends  with  the  anterior 
layer.  The  middle  layer  is  in  the  interval  between  the  sacro-spinal 
mass  and  the  quadratus  lumborum.  It  is  attached  to  the  tips  of  the 
transverse  processes  of  the  lumbar  vertebras.  The  anterior  layer  forms 
the  front  part  of  the  sheath  of  the  quadratus  lumborum,  it  then  passes 
between  that  muscle  and  the  psoas  to  become  attached  to  the  front  of 
the  bases  of  the  transverse  processes  of  the  lumbar  vertebrae. 


FIFTH  LAYER.     (See  Fig.  47) 

Sacro-spinalis  or  Erector  Spinae  (i), — from  the  sacro-iliac  groove,  and  by 
the  lumbo-sacral  tendon  from  the  sacral,  lumbar  and  lower  2  thoracic 
spines,  the  iliac  crest,  and  the  posterior  eminences  of  the  sacrum :  divides 
into  the  ilio-costalis  (2)  and  longissimus  dorsi  (3)  muscles.  Action,  to 
erect  the  spine  and  bend  the  trunk  backward.  Nerves,  external  pos- 
terior branches  of  the  lumbar  nerves. 


MUSCLES  OF  THE  BACK  QI 

ILIO-COSTAL  DIVISION 

Ilio-costalis  Lumbonun  (sacro-lumbalis)  (2), — the  external  portion  of  the 
erector  spinae:  into  the  inferior  borders  of  the  angles  of  the  lower  6  or  7 
ribs.  Action,  as  the  erector  spinae.  Nerves,  branches  of  the  thoracic. 

Ilio-costalis  Dorsi  or  Musculus  Accessorius  ad  Hio-costalem  (2), — from 
the  angles  of  6  lower  ribs:  into  the  angles  of  upper  6  ribs.  Action,  as  the 
erector  spinae.  Nerves,  branches  of  the 
thoracic. 

Ilio-costalis  Cervicis  or  Cervicalis  Ascen- 
dens  (s),—from  the  angles  of  upper  4 
or  5  ribs:  into  the  transverse  processes 
of  the  4th,  5th,  and  6th  cervical  verte- 
brae. Action,  to  keep  the  neck  erect. 
Nerves,  branches  of  the  cervical. 

LONGISSIMUS   DIVISION 

Longissimus  Dorsi  (3). — is  the  middle 
and  largest  portion  of  the  erector  spinae, 
and  is  inserted  into  the  transverse  and 
articular  processes  of  the  lumbar  verte- 
brae, into  the  tips  of  the  transverse  proc- 
esses of  all  the  thoracic  vertebrae,  and 
into  from  lower  7  to  n  ribs  between 
their  tubercles  and  angles.  Action,  as 
the  erector  spinae.  Nerves,  branches  of 
the  lumbar  and  thoracic  nerves. 

Longissimus  Cervicis  or  Transversalis 
Colli  (6), — from  the  transverse  processes 
of  the  upper  6  thoracic  vertebrae;  into  the 
transverse  processes  of  the  cervical  verte- 
brae (9),  from  the  2d  to  the  6th  inclusive. 
Action,  to  keep  the  head  erect.  Nerves, 
branches  of  the  cervical. 

Longissimus  Capitis  or  Trachelo-mastoid 
(7),— from  the  transverse  processes  of 

the  upper  5  or  6  thoracic  vertebrae,  and  the  articular  processes  of  the 
lower  3  or  4  cervical:  into  the  posterior  margin  of  the  mastoid  proc- 
ess of  the  temporal  bone.  Action,  to  steady  the  head.  Nerves, 
branches  of  the  cervical. 


92  HUMAN    ANATOMY 

SPINAL  MASS 

Spinalis  Dorsi,— from  the  last  2  thoracic  and  first  2  lumbar  spines:  into 
all  the  remaining  thoracic  spines.  Action,  to  erect  the  spinal  column. 
Nerves,  branches  of  the  thoracic. 

Spinalis  Cervicis  or  Spinalis  Colli, — from  the  5th,  6th  and  7th  cervical 
spines,  sometimes  from  the  ist  and  2d  thoracic:  into  the  spine  of  the  axis 
and  occasionally  into  the  spines  of  the  next  two  vertebrae  below.  A  ction, 
to  steady  the  neck.  Nerves,  branches  of  the  cervical.  [This  muscle  is 
frequently  absent.] 

Semi -spinalis  Capitis  or  Complexus  (8), — by  7  tendons  from  the  tips  of 
the  transverse  processes  of  the  ;th  cervical  and  upper  6  or  7  thoracic 
vertebrae,  and  from  the  articular  processes  of  the  4th,  5th,  and  6th  cer- 
vical: into  the  inner  depression  between  the  curved  (nuchal)  lines  of  the 
occipital  bone.  Action,  to  retract  and  rotate  the  head.  Nerves,  sub- 
occipital,  great  occipital,  and  branches  of  the  cervical  nerves. 

Bivenler  Crevicis, — is  the  inner  part  of  the  Complexus,  from  the  trans- 
verse processes  of  upper  2  to  4  thoracic  vertebrae:  into  the  superior  curved 
line  of  the  occipital  bone.  Action,  as  the  complexus.  Nerves,  branches 
of  the  cervical. 

Semi -spinalis  Dorsi  (10), — from  the  transverse  processes  of  the  thoracic 
vertebrae,  from  about  the  sth  to  the  nth:  into  the  last  2  cervical  and 
upper  4  thoracic  spines.  Action,  to  erect  the  spinal  column.  Nerves, 
branches  of  the  thoracic  nerves. 

Semi -spinalis  Cervicis  or  Semi-spinalis  Colli  (n), — from  the  transverse 
processes  of  the  upper  5  or  6  thoracic  vertebrae:  into  the  2d,  3d,  4th, 
and  5th  cervical  spines.  Action,  to  erect  the  spinal  column.  Nerves, 
branches  of  the  cervical. 

SIXTH  LAYER 

Multifidus  Spinae  (m.  multifidus)  (i6],—from  the  back  of  the  sacrum,  pos- 
terior superior  spine  of  the  ilium,  posterior  sacro-iliac  ligaments,  ar- 
ticular processes  of  lumbar  and  lower  3  or  4  cervical  vertebrae,  and  the 
transverse  processes  of  the  thoracic:  into  the  spines  of  the  next  4  vertebrae 
above.  Action,  to  erect  and  rotate  the  spinal  column.  Nerves,  branches 
of  the  spinal  nerves. 

Rotatores  Spinae  (mm.  rotatores),— from  the  transverse  processes  of  the 
thoracic  vertebrae,  from  the  2d  to  the  i2th  inclusive:  each  into  the 
lamina  of  the  next  thoracic  vertebrae  above.  Action,  to  rotate  the 
spinal  column.  Nerves,  branches  of  the  posterior  thoracic. 


SUBOCCIPITAL   AND   THORACIC   MUSCLES  93 

Inter-spinales, — placed  in  pairs  between  the  spines  of  contiguous  vertebrae, 
6  pairs  in  the  cervical  region,  3  in  the  thoracic,  4  sometimes  6  in  the 
lumbar.  Nerves,  branches  of  the  posterior  spinal. 

Extensor  Coccygis,— from  the  last  bone  of  the  sacrum  or  first  of  the  coccyx : 
into  the  lower  part  of  the  coccyx,  posteriorly.  Action,  as  named. 
Nerves,  branches  of  the  posterior  sacral. 

Inter -transversales  (mm.  intertransversarii)  (18), — placed  between  the 
transverse  processes  of  contiguous  vertebrae,  7  in  the  cervical  region, 
12  in  the  thoracic,  and  4  in  the  lumbar.  Nerves,  branches  of  the  pos- 
terior spinal. 

SUBOCCIPITAL  MUSCLES 

Rectus  Capitis  Posti'cus  Major  (m.  rectus  capitis  posterior  major)  (13), — 
from  the  spine  of  the  axis:  into  the  inferior  curved  or  nuchal  line  of  the 
occipital  bone  and  the  surface  below.  Action,  to  rotate  the  head. 
Nerves,  suboccipital. 

Rectus  Capitis  Posti'cus  Minor  (m.  rectus  capitis  posterior  minor)  (12), — 
from  the  tubercle  on  the  posterior  arch  of  the  atlas:  into  a  rough  surface 
between  the  foramen  magnum  and  the  inferior  curved  or  nuchal  line  of 
the  occipital  bone.  Action,  to  draw  the  head  backward.  Nerves, 
suboccipital. 

Obliquus  Capitis  Inferior  (15), — from  the  spinous  process  of  the  axis: 
almost  horizontally  into  the  transverse  process  of  the  atlas.  Action,  to 
rotate  the  atlas  and  cranium.  Nerves,  suboccipital. 

Obliquus  Capitis  Superior  (14), — from  the  transverse  process  of  the  atlas, 
upward  and  inward  into  the  occipital  bone  between  the  curved  lines. 
Action,  draws  the  head  backward.  Nerves,  suboccipital. 

Rectus  Capitis  Lateralis, — from  upper  surface  of  lateral  mass  of  atlas:  into 
under  surface  of  the  jugular  process  of  the  occipital  bone.  Action,  to 
flex  the  head  laterally.  Nerve,  the  anterior  branch  of  the  first  cervical. 

MUSCLES  OF  THE  THORAX 

External  Intercostals, — each  from  the  lower  border  of  each  rib:  into 
the  upper  border  of  the  next  rib  below  directed  obliquely  downward  and 
forward.  Action,  to  raise  and  evert  the  ribs  in  inspiration.  Nerves, 
intercostal. 

Internal  Intercostals, — each  from  the  ridge  on  the  inner  surface  of  each  rib: 
into  the  upper  border  of  the  rib  below,  directed  obliquely  downward  and 


HUMAN    ANATOMY 


backward.  Action,  at  sides  of  thorax  to  depress  the  ribs  in  expiration; 
anteriorly  they  raise  the  costal  cartilages.  Nerves,  intercostals. 

Infra -costales, — obliquely  from  inner  surface  of  each  rib:  into  the  inner 
surface  of  the  ist,  2d,  or  3d  rib  below.  Action,  muscles  of  inspiration. 
Nerves,  intercostal.  [These  muscles  vary  in  number  and  length.] 

Triangularis  Sterni,— from  the  posterior  surface  of  the  ensiform  cartilage 
and  lower  third  of  the  sternum,  also  from  the  sternal  ends  of  the  costal 
cartilages  of  the  lower  3  or  4  true  ribs:  into  the  lower  border  and  inner 
surfaces  of  the  2d,  3d,  4th,  sth,  and  6th  costal  cartilages.  A  ction,  to  draw 
down  the  cartilages  in  expiration.  Nerves,  intercostal. 

FIG.  48. 


Levatores  Costarum  (17  Fig.  47), — each  from  the  transverse  process  of  the 
7th  cervical  and  upper  n  thoracic  vertebrae:  into  the  upper  surface  of 
the  next  rib  below,  near  its  angle.  Action,  to  raise  the  ribs.  Nerves, 
intercostal. 

Diaphragm, — from  the  ensiform  cartilage  (4),  inner  surfaces  of  lower  6  or  7 
ribs,  ligamenta  arcuata  (5),  and  by  its  crura  (8,  10),  from  the  bodies  of 
the  lumbar  vertebrae:  into  the  central  or  cordiform  tendon  (2,  3). 
Action,  the  great  muscle  of  respiration  and  expulsion.  Nerves,  the  two 
phrenic,  lower  intercostals  and  phrenic  plexus  of  the  sympathetic. 

OPENINGS  OF  THE  DIAPHRAGM, — include  several  small  openings  and  3  large 
ones;  the 


MUSCLES    OF    THE    ABDOMEN  95 

Aortic   (n),  in  the  middle  line  posteriorly,  and  behind  the  diaphragm; 

transmits  the  aorta,  vena  azygos  major,  and  thoracic  duct.     (Esopha- 

geal  (12),  in  the  muscular  structure,  transmits  the  oesophagus  and  pneu- 

mogastric  nerves.     Opening  for  the  Vena  Cava  (13)  is  the  highest,  and  has 

4  tendinous  margins. 
The  Right  Cms  (8)  transmits  the  greater  and  lesser  splanchnic  nerves  of 

that  side:  the  Left  Cms  (10),  the  greater  and  lesser  splanchnic  nerves  of 

the  left  side  and  the  vena  azygos  minor. 
Descent  of  the  Diaphragm.     Its  central  tendon  does  not  descend  during 

inspiration,  being  connected  with  the  deep  cervical  fascia  by  the  fibrous 

pericardium. 

MUSCLES  OF  THE  ABDOMEN 

Obliquus  Abdominis  Externus-  or  External  Oblique  (12), — from  8  lower 
ribs  by  8  fleshy  digitations:  into  the  anterior  half  of  the  outer  lip  of  the 
crest  of  the  ilium,  and  by  a  broad  aponeurosis  (13)  into  the  ensiform  carti- 
lage, linea  alba,  symphysis  and  spine  of  the  pubes,  and  the  ilio-pectineal 
line.  Its  aponeurosis  is  continuous  with  that  of  the  pectoralis  major 
above;  below  it  forms  Poupart's  (1.  inguinale)  (14)  and  Gimbernat's 
(1.  lacunare)  ligaments,  and  by  the  separation  of  its  fibres  the  external 
abdominal  ring  (15).  Action,  to  compress  the  viscera,  and  flex  the 
thorax  on  the  pelvis,  and  vice  versa.  Nerves,  lower  intercostal. 

Obliquus  Internus  Abdominis  or  Internal  Oblique  (iS),—from  the  lumbo- 
dorsal  fascia,  the  anterior  two-thirds  of  the  middle  lip  of  the  crest  of  the 
ilium,  and  the  outer  half  of  Poupart's  ligament  (1.  inguinale) :  into  the 
cartilages  of  4  lower  ribs;  by  its  aponeurosis  into  the  linea  alba;  and 
leaving  an  arched  border  (20)  over  the  spermatic  cord,  by  the  conjoined 
tendon  (falx  aponeurotica  inguinalis)  (19)  with  the  transversalis  into  the 
pubic  crest  and  the  pectineal  line.  Its  aponeurosis  passes  in  front  of 
the  rectus  abdominis;  the  lowermost  portion,  from  the  level  of  the  semi- 
lunar  fold  of  Douglas  downward,  is  called  the  conjoined  tendon  because 
it  serves  for  the  transversalis  as  well.  It  blends  in  the  linea  alba  with 
the  tendons  of  its  fellow  of  the  opposite  side  and  the  external  oblique 
and  transversalis  of  both  sides.  Action,  same  as  the  external  oblique. 
Nerves,  lower  intercostals,  ilio-hypogastric,  and  sometimes  from  the 
ilio-inguinal. 

Cremaster,— from  the  inner  part  of  Poupart's  ligament  (1.  inguinale),  form- 
ing a  series  of  loops  along  the  outer  side  of  the  spermatic  cord:  into  the 
crest  of  the  pubis  and  the  front  of  the  sheath  of  the  rectus.  Its  origin 
and  insertion  is  precisely  similar  to  that  of  the  lower  fibres  of  the  internal 
oblique,  from  which  it  is  derived  by  the  descent  of  the  testicle.  Action, 
to  raise  the  testicle.  Nerve,  the  genital  branch  of  the  genito-crural. 


96 


HUMAN   ANATOMY 


Transversalis  Abdominis  or  Transversalis,— from  the  outer  third  of 
Poupart's  ligament  (1.  inguinale),  the  anterior  two-thirds  of  the  inner 
lip  of  the  crest  of  the  ilium,  the  cartilages  of  6  lower  ribs,  and  by  its 
dorsal  aponeurosis  (middle  layer  of  the  lumbodorsal  fascia)  from  the 
spines  and  transverse  processes  of  the  lumbar  vertebrae:  by  its  ventral 
aponeurosis  into  the  linea  alba,  and  by  the  conjoined  tendon  (falx  ap- 

FIG.  49. 


oneurotica  inguinalis)  (19)  with  the  internal  oblique,  into  the  pubic  crest 
and  the  pectineal  line.  Its  ventral  aponeurosis  passes  behind  the  rectus 
abdominis  for  about  its  upper  three-fourths;  the  lower  edge  of  this 
tendon  is  the  so-called  "semilunar"  fold  of  Douglas.  Action,  as  the 
external  oblique.  Nerves,  as  the  internal  oblique. 

Rectus  Abdominis  (16), — by  2  tendons  from  the  pubic  crest  and  the  liga- 
ments covering  the  symphysis;  into  the  cartilages  of  the  5th,  6th,  an^ 


MUSCLES    OF    THE    PELVIC    OUTLET  97 

7th  ribs.     It  lies  in  a  sheath  formed  by  the  aponeuroses  of  the  internal 

oblique   and   transversalis   muscles  for  its  upper   three-fourths,   and   is 

crossed  by  3  tendinous  lines,  the  Linece  Transverse.     At  its  outer  border 

is  a  similar  line  placed  vertically,  the  Linea  Semilunaris,  formed  by  the 

blending  of  the  aponeuroses  of  the  internal  oblique  and  transversalis. 

Action,  to  flex  the  thorax  on  the  pelvis  and  vice  versa,  also  to  compress  the 

abdominal  viscera.     Nerves,  lower  intercostal  nerves. 

Pyramidalis  (17), — lies  in  front  of  the  rectus,  but  in  the  same  sheath;  arises 

from  the  front  of  the  pubic  bone  and  the  anterior  pubic  ligament: 

into  the  linea  alba,  half-way  to  the  umbilicus.     Action,  a  tensor  of  the 

linea  alba.     Nerves,  lower  intercostal  nerves. 

Quadratus  Lumborum  (19  Fig.  47), — from  the  ilio-lumbar  ligament,  and 
the  adjacent  2  inches  of  the  crest  of  the  ilium:  into  one-half  of  the  lower 
border  of  the  last  rib,  and  the  transverse  processes  of  the  4  upper  lumbar 
vertebrae.  Action,  to  flex  the  thorax  laterally  on  the  pelvis  and  vice 
versa.  Nerves,  anterior  branches  of  the  last  thoracic  and  ist  lumbar. 
The  Psoas  Magnus,  the  Psoas  Parvus  and  the  Iliacus  muscles  may  be  con- 
sidered deep  muscles  of  the  abdomen,  but  are  described  with  the  muscles 
of  the  lower  extremity. 


MUSCLES  OF  THE  PELVIC  OUTLET 

The  muscles  of  this  region  are  situated  at  the  pelvic  outlet  in  the  ischio- 
rectal  region  and  the  perinaeum. 

MUSCLES  OF  THE  ISCHIO-RECTAL  REGION 

Corrugator  Cutis  Ani, — A  thin  stratum  of  involuntary  muscular  fibre 
around  the  anus,  radiating  from  its  orifice  and  serving  to  raise  the  skin 
into  ridges  around  the  anal  margin. 

External  Sphincter  Ani  (4),— from  the  tip  of  the  coccyx  and  superficial 
fascia:  into  the  tendinous  center  of  the  perinaeum.  Action,  to  close  the 
anus.  Nerves,  inferior  hemorrhoidal  branch  of  the  internal  pudic,  also  a 
branch  from  the  anterior  division  of  the  4th  sacral. 

Internal  Sphincter  Ani, — an  aggregation  of  the  involuntary  circular  fibres 
of  the  intestine,  forming  a  muscular  ring  around  the  rectum  about  an 
inch  above  the  margin  of  the  anus.  Action,  to  occlude  the  anal  aperture. 

[A  third  sphincter,  the  Sphincter  Tertius, — from  the  sacrum,  encircling  the 
rectum  about  4  inches  above  the  anus,  was  demonstrated  by  Velpeau, 
Nelaton  and  Hyrtl,  but  is  denied  by  other  anatomists.] 
7 


98  HUMAN    ANATOMY 

Levator  Ani'(s),— -from  the  body  and  ramus  of  the  pubis  posteriorly,  the 
pelvic  fascia  and  the  spine  of  the  ischium:  into  the  tendinous  centre  of 
the  perinaeum,  the  sides  of  the  rectum  (and  vagina),  apex  of  the  coccyx, 
and  a  fibrous  raphe  extending  from  the  coccyx  to  the  anus.  Action,  to 
support  the  lower  end  of  the  rectum  and  vagina  and  the  bladder,  and 
assist  in  forming  the  floor  of  the  pelvis.  Nerves,  branches  from  the  4th 
sacral  and  pudic. 

Coccygeus, — from  the  spine  of  the  ischium  and  the  lesser  sacro-sciatic  liga- 
ment: into  the  margin  of  the  coccyx  and  the  side  of  the  last  sacral  seg- 

ment.  Action,  to  support  the 
coccyx,  and  close  the  outlet  of 
the  pelvis  posteriorly.  Nerves, 
branches  from  the  4th  and  $th 
sacral. 

MUSCLES  OF  THE  PERINEUM 
IN  THE  MALE 

Superficial  Transversus  Perinaei 

(3),— from  the  tuberosity  of 
the  ischium:  into  the  central 
tendon  of  the  perinaeum.  Ac- 
tion, to  draw  tense  the  central 
tendon.  Nerve,  perinea!  branch 
,of_the  pudic. 

Transversus  Perinaei  Profundus 
(Compressor  Urethrae),— from 
the  junction  of  the  rami  of  the 
pubis  and  ischium:  into  its 
fellow  of  the  opposite  side  after 
encircling  the  membranous  portion  of  the  urethrae.  Action,  to  com- 
press the  veins  of  the  penis,  the  membranous  urethra,  and  Cowper's 
glands.  Nerve,  perineal  branch  of  the  pudic. 

Bullo-cavernosus  (Accelerator  Urinae)  (i), — from  the  central  tendon  of  the 
perinaeum  and  the  median  raphe  anteriorly:  the  fibres  spread  over  the 
bulb,  corpus  spongiosum,  corpus  cavernosum  and  the  dorsal  vessels  of 
the  penis.  Action,  to  accelerate  the  flow  of  urine  and  erect  the  penis. 
Nerve,  perineal  branch  of  the  pudic. 

ischio-cavernosus  or  Erector  Penis  (2), — from  the  tuberosity  and  ramus 
of  the  ischium  and  the  crus  penis:  into  the  crus  penis  laterally  and  infe- 


MUSCLES    OF    THE    UPPER    EXTREMITY  99 

riorly.    Action,  to  maintain  erection  of  the  penis.    Nerve,  perineal  branch 
of  the  pudic. 

FASCIAE  OF  THE  PERINEUM, — are  described  under  the  title  Perinaeum  at 
the  end  of  the  book. 

MUSCLES  OF  THE  PERINEUM  IN  THE  FEMALE 

Superficial  Transversus  Perinsei  (3), — from  the  tuberosity  of  the  ischium 
internally:  into  the  central  point  of  the  perinaeum,  joining  with  its  fellow 
of  the  opposite  side.  Action,  to  fix  the  central  tendinous  point  of  the 
perinaeum.  Nerve,  the  perineal  branch  of  the  pudic. 

Bulbo-cavernosus  or  Sphincter  Vaginae, — surrounds  the  orifice  of  the  va- 
gina, and  is  analogous  to  the  accelerator  urinae  of  the  male.  Arising 
from  the  central  tendon  of  the  perinaeum,  its  fibres  are  inserted  into  the 
corpora  cavernosa  of  the  clitoris,  a  fasciculus  crossing  over  the  body  of 
the  organ  so  as  to  compress  the  dorsal  vein.  Action,  to  diminish  the 
orifice  of  the  vagina.  Nerve,  perineal  branch  of  the  pudic. 

Ischio-cavernosus  or  Erector  Clitoridis, — from  the  tuberosity  andramus  of 
the  ischium  internally :  into  the  crus  clitoridis  by  an  aponeurosis.  A  ction, 
to  erect  the  clitoris  by  retarding  the  return  of  its  blood  supply.  Nerve, 
perineal  branch  of  the  pudic. 

Deep  Transversus  Perinsei  or  Compressor  Urethras, — from  the  margin  of 
the  descending  ramus  of  the  pubic  bone:  into  its  fellow  in  front  of  the 
urethra  and  into  the  wall  of  the  vagina  behind  the  urethra.  Action,  as 
indicated  by  its  name.  Nerve,  perineal  branch  of  the  pudic. 

MUSCLES  OF  THE  UPPER  EXTREMITY 

MUSCLES  OF    THE  THORACIC  REGION 

JL '/  Pectoralis  Major  (i,  2,  3), — from  the  sternal  half  of  the  clavicle,  by  an 
/  /  aponeurosis  from  the  front  of  the  sternum  as  low  as  the  6th  or  yth  rib, 
the  cartilages  of  all  the  true  ribs  (5),  and  the  aponeurosis  of  the  external 
oblique:  the  fibres  converge,  cross  and  are  inserted  by  a  flat  tendon  (4) 
into  the  external  bicipital  ridge  (crest  of  the  great  tubercle)  of  the  hu- 
merus,  having  crossed  the  bicipital  groove  (intertubercular  sulcus). 
Action,  to  draw  the  arm  forward  and  downward;  also  to  elevate  the  ribs 
in  forced  inspiration.  Nerves,  anterior  thoracic. 

Pectoralis  Minor  (6),— from  the  3d,  4th,  and  5th  ribs,  and  the  intercostal 
aponeurosis:  into  the  coracoid  process  of  the  scapula.  Action,  to  depress 


100  HUMAN   ANATOMY 

the  point  of  the  shoulder,  also  to  elevate  the  ribs  in  forced  inspiration. 
Nerves,  anterior  thoracic. 

Subclavius  (7), — from  the  cartilage  of  the  ist  rib:  into  a  deep  groove  on  the 
under  surface  of  the  clavicle.  Action,  to  draw  the  clavicle  downward. 
Nerve,  a  branch  from  the  5th  cervical. 

Serratus  Magnus  (m.  serratus  anterior), — by  9  digitations  (10)  from  the 
8  upper  ribs  (the  2d  rib  having  2)  and  from  the  intercostal  aponeurosis: 
into  the  whole  length  of  the  ventral  aspect  of  the  vertebral  border  of 
the  scapula.  Action,  to  elevate  the  ribs  in  inspiration,  also  to  raise  the 


point  of  the  shoulder.  In  Lhe  lower  animals  it  is  the  great  sling-muscle, 
slinging  the  body  between  the  upper  extremities.  Nerve,  posterior 
thoracic. 

MUSCLES  OF  THE  SHOULDER  AND  ARM 

Deltoid  (8),— from  the  outer  third  of  the  anterior  and  superior  surfaces  of 
the  clavicle,  the  outer  margin  and  upper  surface  of  the  acromion,  and  the 
lower  border  of  the  spine  of  the  scapula:  into  a  prominence  on  the  outer 
side  of  the  shaft  of  the  humerus,  about  its  middle.  Action,  to  raise  the 
arm.  Nerve,  circumflex  (n.  axillaris). 

Subscapularis  (15), — from  the  inner  two-thirds  of  the  subscapular  fossa: 
into  the  lesser  tuberosity  of  the  humerus.  Action,  to  rotate  the  head  of 
the  humerus  inward.  Nerves,  subscapular. 


MUSCLES    OF    THE    UPPER    EXTREMITY 


101 


Supraspinatus,— from  the  inner  two-thirds  of  the  supraspinous  fossa  and 

the  fascia  covering  the  muscle:  into  the  upper  facet  of  the  greater  tuber- 

osity  of  the  humerus.     Action,  to  support  the  shoulder- joint,  and   to 

raise  the  arm.     Nerve,  suprascapular. 
Infraspinatus,— from  the  inner  two-thirds  of  the  infraspinous  fossa  and  the 

covering  fascia:  into  the  middle  facet  on  the  greater  tuberosity  of  the 

humerus.     Action,  to  rotate  the  humerus  out- 
ward.    Nerve,  suprascapular. 
Teres  Minor  (14),— from  the  upper  two-thirds  of 

the  dorsal  surface  of  the  axillary  border  of  the 

scapula:  into  the  lowest  facet  on  the  greater 

tuberosity  of  the  humerus,  and  the  bone  below. 

Action,  to  rotate  the  humerus  outward.     Nerve, 

circumflex  (n.  axillaris). 

Teres  Major, — from  the  dorsal  aspect  of  the  in- 
ferior angle  of  the  scapula:  into   the   internal 

bicipital    ridge    (crest    of    the    small    tubercle) 

of  the  humerus.     Action,  to  assist  the  latissimus 

dorsi.     Nerve,  subscapular. 
Coraco-brachialis   (n), — from    the  apex  of  the 

coracoid  process  (2)  of  the  scapula:  into  a  ridge 

on  the  inner  side  of  the  shaft  of  the  humerus, 

about  its  middle.     Action,  elevates  the  humerus 

forward    and   inward.      Nerve,    musculo-cuta- 

neous,  which  perforates  this  muscle. 
Biceps  (15)  (biceps  flexor  cubiti),— Long  head  (8) 

from  the  upper  margin  of  the  glenoid  cavity; 

short  head  (12)  from  the  apex  of  the  coracoid 

process  (2),  in  common  with  the  coraco-bra- 

chialis :  into  the  back  of  the  tuberosity  of  the 

radius,    and    the   fascia    (20)    of  the  forearm. 

Action,  to  flex    and  supinate  the  forearm,  and 

to  make  tense  its  fascia.     Nerve,  the  musculo- 

cutaneous. 
Brachialis    Anti'cus    (m.   brachialis)    (17),— from 

the  lower  half  of  the  shaft  of  the  humerus  an- 
teriorly and  laterally,  embracing  the  insertion  of  the  deltoid  (9) :  into 

the  base  of  the  coronoid  process  (19)  of  the  ulna.     Action,  a  flexor  of 

the    forearm.       Nerves,    musculo-cutaneous    and    musculo-spiral    (n. 

radialis). 


IO2  HUMAN    ANATOMY 

Triceps  (16)  (triceps  extensor  cubiti), — by  three  heads,  the  outer  (lateral) 
and  inner  (medial)  from  the  posterior  surface  of  the  shaft  of  the  humerus, 
the  outer  above,  the  inner  below  the  musculo-spiral  (radial)  groove; 
the  middle  or  long  head  from  a  depression  (infra-glenoid  tuberosity) 
below  the  glenoid  cavity  of  the  scapula;  by  a  common  tendon  into  the 
upper  end  of  the  olecranon  process  of  the  ulna.  Action,  to  extend  the 
forearm.  Nerve,  musculo-spiral  (n.  radialis). 

Sub-anconeus,— from  the  humerus  above  the  olecranon  fossa:  into  the 
posterior  ligament  of  the  elbow- joint.  Action,  probably  a  tensor  of  the 
ligament.  Nerve,  musculo-spiral  (n.  radialis). 

MUSCLES  OF  THE  FOREARM 

Muscles  of  the  Forearm,  arranged  in  groups  of  5  and  3.     (Pancoast.) 
ANTERIORLY,  5  flexors,  2  pronators,  i  tensor  of  palmar  fascia: — 

Flexor  Carpi  Radialis.    .         j  Pronator  Radii  Teres  (m.  pronator 
Flexor  Carpi  Ulnaris.  \  Pronator  Quadralus.  teres). 

Flexor  Longus  Pollicis.  Palmaris  Longus. 

f  Flexor  Sublimis  Digitorum. 
1  Flexor  Profundus  Digitorum. 

POSTERIORLY  12  muscles  in  4  sets  of  threes: — 

Brachio-radialis  (Supinator  Longus).  Extensor  Indicts. 
Extensor  Carpi  Radialis  Longior.        Extensor  Communis  Digitorum. 
Extensor  Carpi  Radialis  Brevior.         Extensor  Minimi  Digiti. 
Extensor  Ossis  Metacarpi  Pollicis.       Extensor  Carpi  Ulnaris. 
Extensor  Brevis  Pollicis.  Anconeus. 

Extensor  Longus  Pollicis.  Supinator  Brevis. 

Pronator  Radii  Teres  (m.  pronator  teres)  (4), — by  2  heads,  one  from  above 
the  medial  or  internal  condyle  of  the  humerus,  the  common  tendon,  fas- 
cia, and  the  intermuscular  septum;  the  other  from  the  medial  or  inner 
side  of  the  coronoid  process  of  the  ulna:  into  a  rough  ridge  on  the  radial 
or  outer  side  of  the  shaft  of  the  radius,  about  its  middle.  Action,  to 
pronate  the  hand.  Nerve,  median,  which  passes  between  the  2  heads 
of  the  muscle. 

Flexor  Carpi  Radialis  (5),— from  the  medial  or  internal  condyle  of  the 

humerus  by  "the  common  tendon,  the  fascia,  and  the  intermuscular 

septa:  into  the  base  of  the  metacarpal  bone  of  the  index  finger.     Action, 

to  flex  the  wrist.     Nerve,  median. 

Palmaris  Longus  (6), — from  the  same  origin  as  the  flexor  carpi  radialis: 


MUSCLES    OF    THE   FOREARM 


103 


FIG.  S3- 


into  the  annular  ligament  (1.  carpi  transversum)  and  the  palmar  fascia 
(9).     Action,  to  make  the  palmar  fascia  tense.     Nerve,  median. 

Flexor  Carpi  Ulnaris  (8), — by  2  heads,  one  from  the  inner  or  medial  con- 
dyle  of  the  humerus  by  the  common  tendon,  the  other  from  the  inner 
or  medial  margin  of  the  olecranon,  the  upper  two-thirds  of  the  posterior 
border  of  the  ulna,  and  the  intermuscular  septum:  into  the  pisiform 
bone,  the  annular  ligament  (1.  carpi  transver- 
sum), and  the  5th  metacarpal  and  unciform 
(hamate)  bones.  Action,  to  flex  the  wrist. 
Nerve,  ulnar. 

Flexor  Sublimis  Digitorum  (Perforatus)  (7), — by 
3  heads,  one  from  the  medial  or  inner  condyle 
of  the  humerus  by  the  common  tendon,  the 
internal  lateral  or  ulnar  collateral  ligament,  and 
the  intermuscular  septum;  the  second  from  the 
inner  side  of  the  coronoid  process  of  the  ulna; 
the  third  from  the  oblique  line  of  the  radius: 
into  the  lateral  margins  of  the  second  phalanges 
by  4  tendons  which  are  split  for  the  passage  of 
the  deep  flexor  tendons.  Action,  to  flex  the 
second  phalanges.  Nerve,  median. 

Flexor  Profundus  Digitorum  (Perforans),— -from 
the  upper  three-fourths  of  the  shaft  of  the  ulna, 
a  depression  on  the  inner  side  of  the  coronoid 
process,  and  the  interosseous  membrane:  into 
the  bases  of  the  last  phalanges,  by  4  tendons 
which  perforate  the  tendons  of  the  superficial 
flexor.  Action,  to  flex  the  phalanges.  Nerves, 
ulnar,  anterior  interosseous  branch  of  the 
median. 

Flexor  Longus  Pollicis, — from  the  upper  two- 
thirds  of  the  shaft  of  the  radius  and  the  in- 
terosseous membrane:  into  the  base  of  the  last 

phalanx  of  the  thumb,   which  it  flexes.     Nerve,  anterior  interosseous 
branch  of  the  median. 

Pronator  Quadratus,— from  the  oblique  line  on  the  lower  fourth  of  the 
ulna,  and  the  anterior  border  of  the  ulna:  into  the  lower  fourth  of  the 
anterior  border  of  the  shaft  of  the  radius.  Action,  to  pronate  the  hand. 
Nerve,  anterior  interosseous  branch  of  the  median. 


104  HUMAN   ANATOMY 

Brachio-radialis  or  Supinator  Longus  (13), — from  the  upper  two-thirds  of 
the  lateral  or  external  condylar  ridge  of  the  humerus,  and  the  inter- 
muscular  septum;  into  the  base  of  the  styloid  process  of  the  radius. 
Action,  to  supinate  the  hand.  Nerve,  musculo-spiral  (n.  radialis). 

Extensor  Carpi  Radialis  Longior  (e),—from  the  lower  third  of  the  lateral  or 
external  condylar  ridge  of  the  humerus,  and  the  intermuscular  septum: 
into  the  base  of  the  metacarpal  bone  of  the  index 
FlG-  54-  finger  (g),  on  its  radial  side.     Action,  to  extend 

the  wrist.     Nerve,  musculo-spiral  (n.  radialis). 

Extensor  Carpi  Radialis  Brevier  (f),—from  the 
lateral  or  external  condyle  of  the  humerus  by 
the  common  tendon,  the  external  lateral  liga- 
ment, and  the  intermuscular  septa:  into  the 
radial  side  of  the  base  of  the  3d  metacarpal 
bone  (g).  Action,  to  extend  the  wrist.  Nerve, 
posterior  interosseous. 

Extensor  Communis  Digitorum  (h),—from  the 
lateral  or  external  condyle  of  the  humerus  by 
the  common  tendon,  the  deep  fascia,  and  the 
intermuscular  septa:  into  the  2d  and  3d 
phalanges  of  all  the  fingers,  by  3  tendons,  one 
of  which  divides  into  two.  Action,  to  extend 
the  fingers.  Nerve,  posterior  interosseous. 

Extensor  Minimi  Digiti  (m.  extensor  digiti  quinti 
proprius)  (i),—from  the  common  tendon  and 
the  intermuscular  septa:  into  the  2d  and  3d 
phalanges  of  the  little  finger,  with  the  tendon 
derived  from  the  common  extensor.  Action,  as 
named.  Nerve,  posterior  interosseous. 

Extensor  Carpi  Ulnaris  (j),—from  the  common 
tendon,  the  middle  third  of  the  posterior  border 
of  the  ulna,  and  the  deep  fascia  of  the  forearm: 
into  the  base  of  the  5th  metacarpal  bone.    Action, 
to  extend  the  wrist.     Nerve,  posterior  interosseous. 

Anconeus  (£), — from  the  lateral  or  external  condyle  of  the  humerus,  pos- 
teriorly: into  the  side  of  the  olecranon,  and  upper  fourth  of  the  posterior 
surface  of  the  shaft  of  the  ulna.  Action,  to  extend  the  forearm.  Nerve, 
the  musculo-spiral  (n.  radialis). 


MUSCLES    OF    THE   HAND  105 

Supinator  Brevis  (m.  supinator)— from  the  external  condyle  of  the  hu- 
merus,  the  external  lateral  and  orbicular  ligaments  and  an  oblique  line  on 
the  ulna:  into  the  inner  surface  of  the  neck  of  the  radius,  the  outer  edge 
of  its  bicipital  tuberosity,  and  the  oblique  line.  Action,  to  supinate  the 
hand.  Nerve,  posterior  interosseous,  which  pierces  it. 

Extensor  Ossis  Metacarpi  Pollicis  (m.  abductor  pollicis  longus)  (14), — 
from  the  posterior  surfaces  of  the  shafts  of  the  radius  and  ulna,  and  the 
interosseous  membrane:  into  the  base  of  the  metacarpal  bone  of  the 
thumb.  Action,  to  extend  the  thumb.  Nerve,  posterior  interosseous. 

Extensor  Bievis  Pollicis  (Extensor  Primi  Internodii  Pollicis)  (n), — from 
the  posterior  surface  of  the  shaft  of  the  radius  and  the  interosseous  mem- 
brane: into  the  base  of  the  ist  phalanx  of  the  thumb.  Action,  to  extend 
the  thumb.  Nerve,  posterior  interosseous. 

Extensor  Longus  Pollicis  (Extensor  Secundi  Internodii  Pollicis)  (m), — 
from  the  shaft  of  the  ulna  posteriorly  and  the  interosseous  membrane: 
into  the  base  of  the  last  phalanx  of  the  thumb.  Action,  to  extend  the 
thumb.  Nerve,  posterior  interosseous. 

Extensor  Indicis  (m.  extensor  indicis  proprius) ,— from  the  shaft  of  the 
ulna  posteriorly  and  the  interosseous  membrane:  into  the  2d  and  3d 
phalanges  of  the  index  finger  with  the  tendon  of  the  common  extensor. 
Action,  to  extend  the  index  finger.  Nerve,  posterior  interosseous. 

FASCIAE  OF  THE  HAND 

Anterior  Annular  Ligament  (1.  carpi  transversum), — from  the  pisi- 
form and  unciform  (hamate)  bones:  to  the  tuberosity  of  the  scaphoid 
(navicular)  and  the  ridge  on  the  trapezium  (great  multangular). 
Inserted  into  its  anterior  surface  are  parts  of  the  tendons  of  the 
palmaris  longus  and  the  flexor  carpi  radialis,  and  beneath  it  pass  the 
tendons  of  the  superficial  and  deep  flexors  of  the  fingers  and  the 
flexor  longus  pollicis,  also  the  median  nerve.  It  is  continuous  with 
the  palmar  fascia  and  the  deep  fascia  of  the  forearm. 

Posterior  Annular  Ligament  (1.  carpi  dorsale)  (o),—from  the  ulna,  cunei- 
form and  pisiform  bones:  to  the  margin  of  the  radius  and  the  ridges  on 
its  posterior  surface.  It  has  6  canals  for  the  passage  of  the  extensor 
tendons,  each  lined  by  a  synovial  membrane.  It  is  continuous  with  the 
deep  fascia  of  the  forearm. 

Deep  Palmar  Fascia,— ensheaths  the  muscles  of  the  hand,  and  divides 
into  4  slips  for  the  four  fingers,  each  slip  dividing  and  forming  tendinous 
arches  for  the  passage  of  the  flexor  tendons  of  the  fingers. 


106  HUMAN   ANATOMY 

MUSCLES  OF  THE  HAND 

Abductor  Pollicis  (m.  abductor  pollicis  brevis)  (n), — from  the  ridge  of  the 
trapezium  (great  multangular)  the  tuberosity  of  the  scaphoid  (navicu- 
lar)  and  the  annular  ligament  (1.  carpi  transversum) :  into  the  radial 
side  of  the  base  of  the  ist  phalanx  of  the  thumb.  Action,  to  draw  the 
thumb  from  the  median  line.  Nerve,  median. 

Opponens  Pollicis, — from  the  palmar  surface  of  the  trapezium  (great  mult- 
angular) and  the  annular  ligament  (1.  carpi  transversum):  into  the  radial 
side  of  the  metacarpal  bone  of  the  thumb,  for  its  whole  length.  Action, 
as  a  flexor  ossis  metacarpi  pollicis.  Nerve,  median. 

Flexor  Brevis  Pollicis  (12), — the  outer  portion  from  the  lower  border  of  the 
annular  ligament  (1.  carpi  transversum),  the  inner  and  deeper  portion 
from  the  ulnar  side  of  the  ist  metacarpal  bone:  into  both  sides  of  the 
base  of  the  ist  phalanx  of  the  thumb,  by  two  tendons,  each  having  a 
sesamoid  bone  in  it.  Action,  to  flex  the  thumb.  Nerves,  median  and 
ulnar. 

Adductor  Obliquus  Pollicis  (m.  adductor  pollicis), — from  the  os  magnum, 
the  bases  of  the  2d  and  3d  metacarpal  bones,  the  anterior  carpal  liga- 
ments and  the  sheath  of  the  tendon  of  the  flexor  carpi  radialis:  into  the 
ulnar  side  of  the  base  of  the  ist  phalanx  of  the  thumb,  having  a  sesamoid 
bone  in  the  tendon  of  insertion.  Action,  to  draw  the  thumb  toward  the 
median  line.  Nerve,  ulnar. 

Adductor  Transversus  Pollicis,—; from  the  lower  two-thirds  of  the  meta- 
carpal bone  of  the  middle  finger:  into  the  ulnar  side  of  the  base  of  the  ist 
phalanx  of  the  thumb.  Action,  as  the  preceding  muscle.  Nerve,  ulnar. 
[The  above-mentioned  5  muscles  of  the  thumb  occupy  the  radial  side  of 
the  hand  and  form  the  Thenar  Eminence;  the  first  4  of  the  folio  wing- men- 
tioned muscles  occupy  the  ulnar  side  of  the  hand  and  form  the  Hypothe- 
nar  Eminence.] 

Palmaris  Brevis  (10), — from  the  annular  ligament  and  palmar  fascia:  into 
the  skin  on  the  ulnar  border  of  the  palm  of  the  hand.  Action,  to  corru- 
gate the  skin  of  the  hand.  Nerve,  ulnar. 

Abductor  Minimi  Digiti  (m.  abductor  digiti  quinti), — from  the  pisiform 
bone  and  the  tendon  of  the  flexor  carpi  ulnaris:  -into  the  ulnar  side  of 
the  base  of  the  ist  phalanx  of  the  little  finger  and  the  aponeurosis  of  the 
extensor  minimi  digiti.  Action,  as  indicated  by  its  name.  Nerve, 
ulnar. 

Flexor  Brevis  Minimi  Digiti  (m.  flexor  digiti  quinti  brevis),— from  the 
hook  of  the  unciform  bone  and  the  annular  ligament  (1.  carpi  trans- 


MUSCLES    OF    THE    LOWER    EXTREMITY  1 07 

versum) :  into  the  base  of  the  proximal  phalanx  of  the  little  finger,  with 
the  preceding  muscle.  Action,  as  named.  Nerve,  ulnar. 

Opponens  Minimi  Digiti  (m.  opponens  digiti  quinti), — from  the  unciform 
or  hamate  bone  and  the  annular  ligament  (1.  carpi  transversum) :  into 
the  whole  ulnar  margin  of  the  5th  metacarpal  bone.  Action,  a  flexor 
of  the  5th  metacarpal  bone.  Nerve,  ulnar. 

Lumbricales  4, — from  the  tendons  of  the  deep  flexor:  into  the  expanded 
tendons  of  the  common  extensor  on  the  dorsi  of  the  phalanges.  Action, 
to  dorsiflex  the  proximal  phalanges.  Nerves,  median  and  ulnar.  These 
muscles  have  no  sheaths. 

Dorsal  Interossei  4, — by  2  heads  from  the  adjacent  sides  of  the  meta- 
carpal bones:  into  the  bases  of  the  proximal  phalanges  of  the  index, 
middle,  and  ring  fingers,  the  middle  finger  having  two.  Action,  abduc- 
tors of  the  fingers  from  the  median  line  of  the  hand.  Nerve,  ulnar. 

Palmar  Interossei  (mm.  interossei  volares)  3, —from  the  palmar  surfaces 
of  the  2d,  4th,  and  5th  metacarpal  bones:  into  the  bases  of  the  proximal 
phalanges  of  the  same  fingers.  Action,  adductors  of  the  fingers.  Nerve, 
ulnar. 

MUSCLES  OF  THE  LOWER  EXTREMITY 

MUSCLES  AND  FASCIAE  OF  THE  ILIAC  REGION 

ILIAC  FASCIA, — is  an  aponeurotic  layer  which  lines  the  back  of  the  abdom- 
inal cavity  and  covers  the  psoas  and  iliacus  muscles  throughout  their 
whole  extent.  It  is  attached  above  to  the  ligamentum  arcuatum  inter- 
num  (medial  lumbo-costal  arch),  internally  by  arched  processes  to  the 
bodies  of  the  vertebrae,  also  to  the  sacrum  and  the  brim  of  the  true  pelvis; 
externally  it  is  continuous  with  the  lumbar  fascia  above  and  is  attached 
to  the  whole  length  of  the  inner  border  of  the  crest  of  the  ilium;  below 
it  is  continuous  with  the  fascia  transversalis  and  the  pubic  part  of  the 
fascia  lata  of  the  thigh,  is  intimately  connected  to  Poupart's  (1.  inguinale) 
ligament,  and  is  prolonged  backward  and  inward  therefrom  as  a  band, 
the  Ilio-pectineal  Ligament,  to  the  ilio-pectineal  eminence.  It  descends 
behind  the  femoral  vessels  into  the  thigh,  forming  the  posterior  wall  of 
the  femoral  sheath.  Transversalis  Fascia  lines  the  anterior  abdominal 
wall. 

Psoas  Magnus  (m.  psoas  major)  (n},—from  the  bodies,  transverse  proc- 
esses, and  intervertebral  substances  of  the  last  thoracic  and  all  the 
lumbar  vertebrae:  into  the  lesser  trochanter  of  the  femur,  by  a  common 
tendon  with  the  iliacus.  Action,  to  flex  the  thigh  upon  the  pelvis,  and 
when  the  femur  is  fixed  to  bend  the  trunk  forward.  Nerves,  anterior 
branches  of  the  2nd  and  3rd  lumbar. 


108  HUMAN   ANATOMY 

Psoas  Parvus  (m.  psoas  minor),— from  the  bodies  of  the  last  thoracic  and 
first  lumbar  vertebrae  and  the  intervertebral  substance:  into  the  ilio- 
pectineal  eminence  and  the  iliac  fascia.  Action,  when  present  it  is  a 
tensor  of  the  iliac  fascia.  Nerve,  anterior  branch  of  the  ist  lumbar. 

Iliacus  (10), — from  the  iliac  fossa,  inner  margin  of  the  iliac  crest,  ilio-lum- 
bar  ligament,  base  of  the  sacrum,  anterior  spinous  processes  of  the  ilium 
and  the  notch  between  them:  into  the  outer  side  of  the  tendon  of  the 
psoas  magnus,  and  the  capsule  of  the  hip- joint.  Action,  the  same  as 
that  of  the  psoas  magnus.  Nerve,  anterior  crural. 

MUSCLES  AND  FASCIJE  OF  THE  THIGH 

SUPERFICIAL  FASCIA, — forms  a  continuous  fatty  covering  over  the  whole 
thigh,  in  which  lie  the  superficial  vessels  and  nerves.  The  superficial 
layer  is  continuous  above  with  Camper's  fascia  of  the  abdomen.  The 
deep  fibrous  layer  (Scarpa's  fascia)  covers  the  saphenous  opening  in 
the  fascia  lata  (see  below),  where  it  is  perforated  for  the  internal 
saphenous  vein  and  numerous  vessels,  and  is  therefore  called  the  Crib- 
riform Fascia  in  this  situation.  It  forms  one  of  the  coverings  of 
a  femoral  hernia. 

FASCIA  LATA, — the  deep  fascia  of  the  thigh,  extends  from  Poupart's  liga- 
ment to  the  prominent  points  around  the  knee-joint,  and  from  the  mar- 
gin of  the  sacrum  and  coccyx  around  the  limb  to  the  pubic  arch  and 
pectineal  line.  It  sends  two  strong  intermuscular  septa  down  to  the 
linea  aspera,  and  contains  the  Saphenous  Opening  (fossa  ovalis),  which 
is  formed  by  the  reflected  margins  of  its  pubic  and  iliac  portions.  The 
structure  named  PouparCs  Ligament  (1.  inguinale)  is  made  by  the  knife, 
and  is  only  the  line  of  junction  between  the  aponeurosis  of  the  external 
oblique  muscle  and  the  fascia  lata;  extending  from  the  anterior  superior 
spine  of  the  ilium  to  the  spine  of  the  pubic  bone. 

Tensor  Vaginae  Femoris  (m.  tensor  fasciae  latae)  (4), — from  the  anterior 
part  of  the  outer  lip  of  the  iliac  crest,  the  anterior  superior  spinous 
process  and  part  of  the  notch  below  it,  also  from  the  fascia  covering 
the  gluteus  medius:  into  the  fascia  lata,  between  its  two  layers,  about 
one-fourth  down  the  outer  side  of  the  thigh.  Action,  a  tensor  of  the 
fascia  lata.  Nerve,  superior  gluteal. 

Sartorius  (5),— -from  the  anterior  superior  spine  of  the  ilium  (2)  and  half  of 
the  notch  below  it :  into  the  upper  internal  surface  of  the  shaft  of  the  tibia. 
Action,  to  flex  and  cross  the  legs.  Nerve,  anterior  crural. 

Quadriceps  Extensor  (m.  quadriceps  femoris), — including  the  4  remain- 
ing muscles  on  the  front  of  the  thigh, — the  rectus  femoris,  vastus  exter- 


MUSCLES    OF    THE    THIGH 


FIG.  55. 


nus  (m.  vastus  lateralis),  vastus  interims  (m.  vastus  medialis),  and  the 

crureus    (m.    vastus   intermedius).     Its   tendon   is   inserted   into    the 

patella.     Action,  the  great  extensor  of  the  leg.     Nerve,  anterior  crural. 
Rectus  Femoris  (6), — by  two  tendons,  the  Straight 

from  the  anterior  inferior  spine  of  the  ilium,  the 

Reflected  from  a  groove  above  the  brim  of  the 

acetabulum:   into   the   patella  by   a   flattened 

tendon    (9)    which  is  common  to  this  and  the 

next   3    muscles.     Action,    to   extend   the   leg. 

Nerve,  anterior  crural  (n.  femoralis). 
Vastus  Externus  (m.  vastus  lateralis)  (7),— from 

the  anterior  border  of  the  great  trochanter  and 

part  of  the  linea  aspera  of  the  femur:  into  the 

outer  border  of  the  patella,  by  a  flat  tendon 

which  blends  with  the  great  extensor  tendon. 

Action,    to  extend    the    leg.      Nerve,    anterior 

crural  (n.  femoralis). 
Vastus  Interims  (m.  vastus  medialis)  (8),— from 

the  anterior  intertrochanteric   line,   the  spiral 

line,  the  linea  aspera,  the  internalsupracondylar 

line,  the  tendon  of  the  adductor  magnus  and  the 

intermuscular  septum:  into  the  inner  border  of 

the    patella    and    the    great    extensor    tendon. 

Action,  to  extend  the  leg.     Nerve,  anterior  crural 

(n.   femoralis). 
Crureus  (m.  vastus  intermedius), — from  the  upper 

two-thirds  of  the  shaft  of  the  femur  and  the 

intermuscular  septum:  into  the  great  extensor 

tendon.     Action,  to  extend  the  leg.     Nerve,  an- 
terior crural.     This  muscle  and  the  vastus  in- 

ternus  appear  to  be  inseparably  united,   but 

they  can  be  separated. 
Subcrureus  (m.  articularis  genu), — often  blended  with  the  crureus :  from 

the  lower  part   of  the  shaft  of  the  femur  anteriorly; — into  the  capsular 

ligament  behind  the  patella.     Action,  to  draw  up  the  capsular  ligament. 

Nerve,  anterior  crural. 
Oracilis  (15),— from  the  margin  of  the  symphysis  and  the  anterior  half  of 

the  pubic  arch:  into  the  inner  surface  of  the  shaft  of  the  tibia  below  the 

tuberosity  ( medial  condyle).     Action,  to  flex  theleg  and  rotate  it  in  ward, 

also  to  adduct  the  thigh.     Nerve,  obturator. 


no 


HUMAN    ANATOMY 


FIG.  56. 


Pectineus  (12),— -from  the  ilio-pectineal  line,  and  the  bone  in  front  thereof, 
also  from  the  fascia  covering  the  muscle:  into  the  rough  line  extending 
from  the  trochanter  minor  to  the  linea  aspera.  Action,  to  adduct  the 
thigh  and  rotate  it  outward.  Nerves,  accessory  obturator,  anterior 
crural  (n.  femoralis). 

Adductor  Longus  (13), —from  the  front  of  the  os  pubis:  into  the  middle 
third  of  the  linea  aspera.  Action,  to  adduct  the  thigh  powerfully. 
Nerve,  obturator. 

Adductor  Brevis, — from  the  body  and  descending  ramus  of  the  os  pubis; 
into  the  upper  part  of  the  linea  aspera.  Action, 
to  adduct  the  thigh.  Nerve,  obturator. 
Adductor  Magnus  (14),— from  the  descending 
ramus  of  the  os  pubis,  the  ramus  of  the  ischium, 
and  the  outer  margin  and  under  surface  of  the 
tuberosity  of  the  ischium:  into  the  rough  line 
leading  from  the  great  trochanter  to  the  linea 
aspera,  the  whole  length  of  the  linea  aspera,  and 
by  a  tendon  into  the  tubercle  on  the  inner 
condyle  of  the  femur.  Action,  to  adduct  the 
thigh  and  rotate  it  outward.  Nerves,  obturator 
and  great  sciatic.  This  muscle  is  pierced  by  4 
apertures  for  the  3  superior  perforating  and  the 
prof unda  arteries,  and  about  the  lower  one-third 
of  its  insertion  an  angular  interval  is  left 
therein,  the  lower  opening  of  Hunter's  canal 
(femoral  canal),  for  the  passage  of  the  femoral 
vessels  into  the  popliteal  space. 

MUSCLES  OF  THE  HIP 

Gluteus  Maximus  (m.  glutseus  maximus)  (b), — 
from  the  posterior  gluteal  line  of  the  ilium,  the 
crest  behind  it,  the  last  piece  of  the  sacrum,  the 
side  of  the  coccyx,  the  great  sacro-sciatic  liga- 
ment, the  aponeurosis  of  the  erector  spinae  and 
the  fascia  covering  the  gluteus  medius :  into  the 
fascia  lata  and  the  rough  line  leading  from  the 
great  trochanter  to  the  linea  aspera.     Action,  to  extend  and  abduct  the 
thigh  and  rotate  it  outward,  also  to  maintain  the  trunk  erect.     Nerves, 
inferior  gluteal  from  the  sacral  plexus. 
Gluteus  Medius  (m.  glutaeus  medius)  (a},— from  the  ilium  between  the 


MUSCLES    OF    THE   HIP 


III 


posterior  gluteal  and  the  anterior  gluteal  lines,  the  crest  between  them, 
and  the  fascia  of  the  part:  into  the  oblique  lines  on  the  great  trochanter. 
Action,  its  posterior  fibres  rotate  the  thigh  outward,  its  anterior  fibres 
rotate  inward.  It  also  abducts  the  thigh  and  draws  it  forward,  and 
assists  to  maintain  the  trunk  erect.  Nerve,  superior  gluteal. 

Gluteus  Minimus  (m.  glutaeus  minimus)  (8) —from  the  ilium  between  the 
anterior  and  inferior  gluteal  lines,  and  the  margin  of  the  great  sacro- 
sciatic  notch:  into  the  anterior  border  of  the  great  trochanter.  Action, 
to  rotate  the  thigh  inward,  also  to  abduct  and  draw  it  forward,  and  to 
maintain  the  trunk  erect.  Nerve,  superior  gluteal. 

Pyriformis  (9), — by  3  digitations  from  the  front  of  the  sacrum,  from  the 
margin  of  the  great  sacro-sciatic  foramen  and  the  great  sacro-sciatic 
ligament  (1.  sacro-tuberosum) :  into  the  upper  border  of  the  great  tro- 
chanter (7),  having  passed  through  the  great  sacro-sciatic  foramen. 
Action,  an  external  rotator  of  the 

thigh.      Nerves,    first    and    second  FIG.  57. 

sacral. 


Obturator  Interims  (n), — from  the 
posterior  bony  margin  of  the  ob- 
turator foramen  and  the  inner  sur- 
face of  the  obturator  membrane:  into 
the  great  trochanter  (7),  passing 
through  the  lesser  sacro-sciatic  fora- 
men. Action,  an  external  rotator  of 
the  thigh.  Nerve,  a  special  nerve 
from  sacral  plexus  to  the  obturator 
internus. 

Gemellus  Superior  (io),from  the  outer 
surface  of  the  spine  of  the  ischium: 
into  the  great  trochanter,  being 
blended  with  the  tendon  of  the  ob- 
turator internus.  Action,  an  ex- 
ternal rotator  of  the  thigh.  Nerve, 
the  special  nerve  to  the  obturator 
internus  from  the  sacral  plexus. 

Gemellus  Inferior  (12),  from  the  tuberosity  of  the  ischium:  into  the 
tendon  of  the  obturator  internus  and  the  great  trochanter.  Action, 
an  external  rotator  of  the  thigh.  Nerve,  the  special  nerve  from  the 
sacral  plexus  to  the  quadratus  femoris. 


112  HUMAN    ANATOMY 

Quadratus  Femoris  (13),— from  the  tuberosity  of  the  ischium:  into  the 
upper  part  of  the  linea  quadrata  on  the  trochanter  major  posteriorly. 
Action,  an  external  rotator  of  the  thigh.  Nerves,  a  special  branch  of 
the  sacral  plexus. 

Obturator  Externus, — from  the  anterior  inner  bony  margin  of  the  ob- 
turator foramen,  and  the  inner  two-thirds  of  the  anterior  surface  of  the 
obturator  membrane:  into  the  trochanteric  or  digital  fossa  of  the  femur. 
Action,  an  external  rotator  of  the  thigh.  Nerve,  obturator. 

Biceps  (m.  biceps  femoris)  (16), — by  2  heads,  the  Long  Head  (d)  from  the 
tuberosity  of  the  ischium  posteriorly,  the  Short  Head  (e)  from  the  outer 
lip  of  the  linea  aspera,  and  the  intermuscular  septum:  into  the  outer 
side  of  the  head  of  the  fibula;  its  tendon  embracing  the  external  lateral 
(fibular  collateral)  ligament  of  the  knee-joint  and  forming  the  Outer 
Hamstring,  the  tendons  of  the  semi-tendinosus,  semi-membranosus, 
gracilis  and  sartorius  forming  the  Inner  Hamstring.  Action,  to  flex 
the  leg  and  rotate  it  outward.  Nerve,  great  sciatic. 

Semi-tendinosus  (f),—from  the  tuberosity  of  the  ischium  by  a  tendon 
(4)  common  to  it  and  the  long  head  of  the  biceps,  and  from  the  adjacent 
aponeurosis:  into  the  shaft  of  the  tibia  at  its  upper  and  inner  surface, 
its  tendon  curving  around  the  inner  tuberosity  (medial  condyle). 
Action,  to  flex  the  leg  upon  the  thigh.  Nerve,  great  sciatic. 

Semi-membranosus  (g), — from  the  tuberosity  of  the  ischium  above  the 
origin  of  the  above-named  two  muscles:  into  the  inner  tuberosity  (medial 
condyle)  of  the  tibia;  its  tendon  of  insertion  giving  off  fibrous  expan- 
sions one  to  the  outer  condyle  of  the  femur  forming  part  of  the  pos- 
terior ligament  of  the  knee-joint,  another  to  the  fascia  .covering  the 
popliteus  muscle,  and  fibres  to  the  internal  lateral  (tibial  collateral) 
ligament  of  the  joint.  Action,  to  flex  the  leg,  and  rotate  it  inward. 
Nerve,  great  sciatic. 

External  Rotators  of  the  Hip-joint  are  13^, — the  3  adductors,  pyriformis, 
2  obturators,  2  gemelli,  quadratus  femoris,  pectineus,  psoas  magnus, 
iliacus,  sartorius,  and  posterior  half  of  the  gluteus  medius. 

Internal  Rotators  of  the  Hip-joint  are  2^, — the  tensor  vaginae  femoris, 
gluteus  minimus,  and  the  anterior  half  of  the  gluteus  medius. 

MUSCLES  OF  THE  LEG 

Tibialis  Anti'cus  (m.  tibialis  anterior)  (3),— -from  the  outer  tuberosity 
(lateral  condyle)  and  upper  two-thirds  of  the  shaft  of  the  tibia  externally, 
the  interosseous  membrane,  deep  fascia,  and  intermuscular  septum; 
through  the  inner  canal  in  the  anterior  annular  ligament  (11.  transversum 


MUSCLES    OF    THE    LEG 


PIG.  58. 


et  cruciatum  cruris) :  into  the  inner  and  plantar  surface  of  the  internal 
cuneiform  bone,  and  the  base  of  the  ist  metatarsal.  Action,  to  flex 
the  tarsus  on  the  leg,  and  elevate  the  inner  border  of  the  foot.  Nerve, 
anterior  tibial. 

Extensor  Proprius  Hallucis  (m.  extensor  hallucis  longus)  (5),— from  the 
middle  two-fourths  of  the  fibula  anteriorly  and  the  interosseous  mem- 
brane, through  the  2d  canal  in  the  anterior  annular  ligament:  (1.  trans- 
versum  cruris  et  1.  cruciatum  cruris) :  into  the  base  of  the  terminal  or 
distal  phalanx  of  the  great  toe.  Action,  to 
extend  that  toe.  Nerve,  anterior  tibial  (deep 
peroneal  nerve). 

Extensor  Longus  Digitorum  (m.  extensor  digi- 
torum  longus)  (4), — from  the  outer  tuberosity 
(lateral  condyle)  of  the  tibia  the  upper  three- 
fourths  of  the  extensor  surface  of  the  shaft  of 
the  fibula  anteriorly,  interosseous  membrane, 
deep  fascia,  and  intermuscular  septa:  into  the 
2d  and  3d  phalanges  of  the  4  lesser  toes,  by  4 
tendons  which  pass  over  the  dorsum  of  the 
foot  from  the  outer  canal  in  the  anterior  an- 
nular ligament  (11.  transversum  et  cruciatum 
cruris).  Action,  to  extend  the  lesser  toes. 
Nerve,  anterior  tibial  (deep  peroneal). 

Peroneus  Tertius  (m.  peronasus  tertius)  (6), — 
from  the  outer  lower  fourth  of  the  extensor 
surface  of  the  fibula,  interosseous  membrane 
and  intermuscular  septum:  into  the  base  of 
the  5th  metatarsal  bone.  This  muscle  is  a 
part  of  the  last-named,  and  passes  through  the 
same  canal  in  the  annular  ligament  (11.  trans- 
versum et  cruciatum  cruris).  Action,  to  dorsi- 
flex  the  tarsus.  Nerve,  anterior  tibial  (deep 
peroneal). 

Gastrocnemius, — by  2  heads  (9,  10),  from  the 
condyles  of  the  femur,  and  the  supra-condylar 
ridges:  unites  with  the  tendon  of  the  soleus  to  form  the  tendo  Achillis, 
into  the  posterior  tuberosity  of  the  os  calcis  (calcaneus).  Action,  to 
extend  the  foot  or  flex  the  calcaneus.  Nerve,  internal  popliteal  (n. 
tibialis). 

/  Soleus,— from  the  head  and  upper  third  of  the  flexor  surface  of  the  shaft 
8 


HUMAN   ANATOMY 


FIG.  59. 


of  the  fibula  posteriorly,  the  oblique  line  of  the  tibia,  and  the  tendinous 
arch:  unites  with  the  tendon  of  the  gastrocnemius  as  the  tendo  A  chillis 
(see  above).  Action,  to  extend  the  foot  and  flex  the  heel.  Nerves, 
internal  popliteal,  posterior  tibial  (nn.  tibialis). 

Plantaris, — from  the  outer  bifurcation  of  the  linea  aspera  and  the  posterior 
ligament  of  the  knee-joint:  by  a  very  long,  delicate  tendon  into  the 
posterior  surface  of  the  os  calcis.  Action,  to  extend  the  foot  and  flex  the 
heel.  Nerve,  internal  popliteal  (n.  tibialis). 

Popliteus  (6  Fig.  59), — from  a  depression  on  the  external  (lateral)  condyle 
of  the  femur,  and  the  posterior  ligament  of  the  knee- 
joint:  into  the  inner  two-thirds  of  the  triangular  surface 
on  the  shaft  of  the  tibia  (2)  posteriorly  and  above  the 
oblique  line.  Action,  to  flex  the  leg.  Nerve,  internal 
>  popliteal  (n.  tibialis). 

Flexor  Longus  Hallucis  (m.  flexor  hallucis  longus)  (9), — 
from  the  lower  two-thirds  of  the  flexor  surface  of  the 
shaft  of  the  fibula,  the  interosseous  membrane,  fascia, 
and  intermuscular  septum,  its  tendon  passing  through 
grooves  in  the  tibia,  astragalus  and  os  calcis:  into  the 
base  of  the  last  phalanx  of  the  great  toe.  Action,  to 
flex  the  great  toe.  Nerve,  posterior  tibial  (n.  tibialis). 
Flexor  Longus  Digitorum  (m.  flexor  digitorum  longus) 
(7) —from  the  shaft  of  the  tibia  posteriorly  and  below 
the  oblique  line;  its  tendon  passing  behind  the  inner 
I?  malleolus  in  a  groove  (13)  with  the  tibialis  posticus 

(m.  tibialis  posterior):  into  the  bases  of  the  last 
phalanges  of  the  lesser  toes  by  4  tendons  which  per- 
forate the  tendons  of  the  flexor  brevis  digitorum. 
Action,  to  flex  the  phalanges  and  extend  the  foot. 
I  Nerve,  posterior  tibial  (n.  tibialis). 
Tibialis  Posti'cus  (m.  tibialis  posterior)  (8), — by  two 
processes  between  which  pass  the  anterior  tibial  ves- 
sels, from  the  upper  half  of  shaft  of  the  tibia  poste- 
riorly, the  upper  two-thirds  of  the  flexor  surface  of  the 
shaft  of  the  fibula  internally,  the  interosseous  mem- 
brane, deep  fascia,  and  intermuscular  septa;  its  ten- 
don passes  behind  the  inner  malleolus  in  a  groove  (13)  with  the  long 
flexor:  into  the  tuberosity  of  the  scaphoid  and  internal  cuneiform  bones. 
Action,  to  extend  the  tarsus  and  invert  the  foot.  Nerve,  posterior  tibial 
(n.  tibialis). 


MUSCLES    OF   THE   LEG  115 

Peroneus  Longus  (m.  peronaeus  longus)  (io),—from  the  head  of  the  fibula, 
and  the  upper  two-thirds  of  the  peroneal  surface  of  its  shaft  externally, 
the  deep  fascia  and  intermuscular  septa,  passes  behind  the  outer  malleo- 
lus  in  a  groove  with  the  peroneus  brevis,  through  a  groove  in  the  cuboid 
bone:  into  the  outer  side  of  the  base  of  the  metatarsal  bone  of  the  great 
toe  and  the  internal  cuneiform  bone,  having  crossed  the  sole  of  the  foot 
obliquely.  Action,  to  extend  and  evert  the  foot  and  flex  the  heel. 
Nerve,  musculo-cutaneous  branch  of  the  external  popliteal  (n.  peronaei 
superficialis). 

/Peroneus  Brevis  (m.  peronaeus  brevis)  (n), — from  the  middle  third  of  the 
peroneal  surface  of  the  shaft  of  the  fibula  externally  and  the  inter- 
muscular  septa:  its  tendon  passes  behind  the  external  malleolus  in  a 
groove  with  the  long  peroneal,  into  the  dorsum  of  the  base  of  the  5th 
metatarsal  bone.  Action,  to  extend  the  foot.  Nerve,  musculo-cutane- 
ous branch  of  the  external  popliteal  (n.  peronaei  superficialis). 

FASCIA  OF  THE  FOOT 

ANTERIOR  ANNULAR  LIGAMENT  (11.  transversum  et  cruciatum  cruris) 
(12  Fig.  58), — consists  of  vertical  and  horizontal  portions,  is  attached 
to  the  lower  ends  of  the  fibula  and  tibia,  the  os  calcis  and  the  plantar 
fascia.  It  contains  sheaths  lined  by  synovial  membranes  for  the  ten- 
dons of  the  extensor  muscles  (that  of  the  extensor  proprius  hallucis 
passing  beneath  it),  as  also  the  anterior  tibial  vessels  and  nerve. 

INTERNAL  ANNULAR  LIGAMENT  (1.  laciniatum),— from  the  inner  malleolus 
to  the  os  calcis  (calcaneus),  converting  4  bony  grooves  into  canals  lined 
by  synovial  membranes  for  the  flexor  tendons  and  the  posterior  tibial 
vessels  and  nerves. 

EXTERNAL  ANNULAR  LIGAMENT  (1.  peronaei  retinaculum  superior),— front 
the  outer  malleolus  to  the  os  calcis,  binding  down  the  peronei  tendons 
in  one  synovial  sac. 

i  /  PLANTAR  FASCIA, — the  densest  in  the  body,  divided  into  a  central  and  two 

lateral  portions,  and  attached  to  the  inner  tuberosity  of  the  os  calcis, 

f     divides  into  5  processes,  i  for  each  toe,  and  several  intermuscular  septa. 

^  DORSAL  FASCIA, — is  a  thin  membranous  layer  continuous  above  with  the 

anterior  margin  of  the  annular  ligament,  and  becoming  gradually  lost 

opposite  the  heads  of  the  metatarsal  bones,  and  on  each  side  blending 

with  the  plantar  fascia.     It  forms  a  sheath  for  the  tendons  on  the  dorsum 

of  the  foot. 

MUSCLES  or  THE  FOOT 

Extensor  Brevis  Digitorum  (m.  extensor  digitorum  brevis)  (n  Fig.  58), — 
the  only  muscle  on  the  dorsum  of  the  foot,  arises  from  the  os  calcis 


Il6  HUMAN    ANATOMY 

externally,  the  calcaneo-astragaloid  and  the  anterior  annular  ligaments 
(1.  cruciatum  cruris): — by  4  tendons,  i  into  the  proximal  phalanx  of 
the  great  toe,  and  the  others  into  the  outer  sides  of  the  long  extensor 
tendons  of  the  2d,  3d,  and  4th  toes.  A  ction,  to  extend  the  toes.  Nerve, 
anterior  tibial  (deep  peroneal). 
Muscles  on  the  sole  of  the  foot  number  19;  arranged  by  layers: — 

ist  Layer  3d  Layer 

Abductor  Hallucis.  Flexor  Brevis  Hallucis  (m.  flexor  hallu- 

cis  brevis). 

Flexor   Brevis   Digitorum    (m.  Adductor  Obliquus  Hallucis  (caput  obli- 

flexor     digitorum     brevis).  quum  m.  adductoris  hallucis). 

Abductor   Minimi   Digiti    (m.  Flexcr  Brevis  Minimi  Digiti  (m.  flexor 

abductor  digiti  quinti).  digiti  quinti  brevis). 

2d  Layer  Adductor     Transfer sus  Hallucis  (caput 

Flexor  Accessorius  (m.  quad-  transversum  m.  adductoris  hallucis). 

ratus  plantae).  4th  Layer 

Lumbricales,  4.  Interossei  (4  Dorsal,  3  Plantar). 

Abductor  Hallucis,*- from  the  inner  tubercle  of  the  os  calcis  (calcaneus), 
the  internal  annular  ligament  (1.  laciniatum),  plantar  fascia,  and  inter- 
muscular  septum:  into  the  inner  side  of  the  base  of  the  ist  phalanx  of 
the  great  toe.  Action,  to  abduct  the  great  toe.  Nerve,  internal  plantar 
(n.  plantaris  medialis). 

Flexor  Brevis  Digitorum  (m.  flexor  digitorum  brevis),— from  the  inner 
tubercle  of  the  os  calcis  (calcaneus)  (n),  the  plantar  fascia  and  inter- 
muscular  septa:  into  the  sides  of  the  2d  phalanges  of  the  lesser  toes  by  4 
tendons  (5)  which  are  perforated  for  the  long  flexor  tendons  (2).  Action, 
to  flex  the  lesser  toes.  Nerve,  internal  plantar  (n.  plantaris  medialis). 

Abductor  Minimi  Digiti  (m.  abductor  digiti  quinti),— from  the  tubercles 
and  under  surface  of  the  os  calcis  (calcaneus)  (n),  the  plantar  fascia  and 
the  intermuscular  septum:  into  the  base  of  the  proximal  phalanx  of  the 
little  toe  with  the  tendon  of  its  short  flexor.  Action,  to  abduct  the  little 
toe.  Nerve,  external  plantar  (n.  plantaris  lateralis). 

Flexor  Accessorius  (m.  quadratus  plantae)  (i), — by  2  heads,  from  the  os 
calcis  (calcaneus)  and  the  long  plantar  ligament :  into  the  tendon  of  the 
flexor  longus  digitorum.  Action,  accessory  flexor  of  the  toes.  Nerve, 
external  plantar  (n.  plantaris  lateralis). 

Lumbricales  (4),  iour,from  the  long  flexor  tendons:  each  into  the  dorsum  of 
the  proximal  phalanx  of  the  corresponding  toe.  Action,  accessory 


MUSCLES    OF    THE    FOOT  1 17 

flexors  of  the  toes  and  to  dorsiflex  the  proximal  phalanges.  Nerves,  in- 
ternal plantar  (n.  plantaris  medialis)  to  the  innermost  lumbrical, 
external  plantar  (n.  plantaris  lateralis)  to  the  other  three. 

Flexor  Brevis  Hallucis   (m.  flexor  hallucis  brevis)  (7),— -from  the  cuboid 

and  external  cuneiform  bones,  and  the  prolonged  tendon  of  the  tibialis 

posticus  (m.  tibialis  posterior) :  into  both  sides  of  the  base  of  the  proximal 

phalanx  of  the  great  toe,  by  2  portions,  of  which  one  blends  with  the 

abductor  hallucis,  the  other  with  the  adductor  ob- 

liquus   hallucis.     Action,   to   flex   the    great  toe. 

Nerve,  internal  plantar  (n.  plantaris  medialis). 
Adductor  Obliquus  Hallucis  (caput  obliquum  m. 

adductoris    hallucis), — from    the   tarsal   ends   of 

the    three    middle    metatarsal    bones,    and    the 

sheath    of    the    tendon  of  the  peroneus  longus: 

into    the    base    of    the   proximal  phalanx  of  the 

great    toe,    externally.     Action,    to    adduct    the 

great  toe.     Nerve,  external  plantar  (n.  plantaris 

lateralis) . 
Flexor  Brevis  Minimi  Digiti  (m.  flexor  digiti  quinti 

brevis)  (6), — from  the  base  of  the  5th  metatarsal 

bone  (9)  and  the  sheath  of  the  tendon  of  the  pero- 
neus   longus:    into     the    base    of    the    proximal 

phalanx  of  the  little  toe  externally.     Action,   to 

flex   the  little  toe.     Nerve,   external  plantar   (n. 

plantaris  lateralis.) 
Adductor  Transversus  Hallucis  (caput  transversum 

m.  adductoris  hallucis)  (Transversus  Pedis),— from 

the   inferior   metatarso-phalangeal   ligaments    of 

the  three  outer  toes  and  the  transverse  ligament  of  the  metatarsus: 

into  the  outer  side  of  the  proximal  phalanx  of  the  great  toe,  blending  with 

the  tendon  of  the  adductor  obliquus  hallucis.     Action,  to  adduct  the 

great  toe.     Nerve,  external  plantar  (n.  plantaris  lateralis). 

Dorsal  Interossei  (4), — each  by  two  heads  from  the  adjacent  sides  of 
two  metatarsal  bones:  into  the  base  of  the  proximal  phalanx  of  the 
corresponding  toe.  Action,  to  abduct  the  toes.  Nerve,  external  plantar. 

Plantar  Interossei  3,— from  the  shafts  of  the  3d,  4th,  and  5th  metatarsai 
bones:  into  the  bases  of  the  proximal  phalanges  of  the  same  toes.  Ac- 
tion, to  adduct  the  toes  toward  the  median  line.  Nerve,  external  plantar 
(n.  plantaris  lateralis). 


Il8  HUMAN   ANATOMY 

THE  BLOOD-VASCULAR  SYSTEM 
THE  HEART  OR  COR 

The  Pericardium  is  a  conical  membranous  sac,  containing  the  heart  and 
the  roots  of  the  great  vessels.  It  lies  behind  the  sternum  and  between  the 
plurae,  its  apex  upward,  its  base  attached  to  the  central  tendon  of  the  dia- 
phragm. It  is  composed  of  an  outer  fibrous  coat,  and  an  inner  serous  one; 
the  former  is  prolonged  on  the  outer  surfaces  of  the  great  vessels,  except 
the  inferior  vena  cava,  and  becomes  continuous  with  the  deep  layer  of  the 
cervical  fascia;  the  latter  consists  of  a  parietal  layer,  lining  the  inner  sur- 
face of  the  fibrous  coat,  and  a  visceral  layer,  which  is  reflected  over  the 
heart  and  vessels.  The  serous  portion  secretes  a  thin  fluid,  about  i  drachm 
in  quantity  normally,  for  the  lubrication  of  its  surfaces.  Arteries,  are 
derived  from  the  internal  mammary  and  its  musculo-phrenic  branch,  and 
from  the  descending  thoracic  aorta.  Nerves,  are  branches  from  the  vagus, 
the  phrenic  and  the  sympathetic. 

The  Endocardium  is  a  thin,  smooth,  transparent  membrane,  which  lines 
the  internal  surface  of  the  heart;  assisting  by  its  reduplications  in  forming 
the  valves,  and  being  continuous  with  the  lining  membrane  of  the  great 
blood-vessels. 

JThe  Heart  (cor)  is  a  hollow  muscular  organ,  conoidal  in  shape,  placed 
obliquely  in  the  chest  between  the  lungs,  base  upward,  apex  to  the  left  and 
front,  corresponding  to  the  space  between  the  5th  and  6th  costal  cartilages, 
%  inch  inside  of  and  i^  inch  below  the  left  nipple.  In  the  adult  its  size 
is  about  5  inches  by  3^  by  2%,  and  from  10  to  12  oz.  in  weight  in  the  male, 
8  to  10  oz.  in  the  female. 

The  Cavities  of  the  Heart  are  4  in  number,  an  atrium  and  ventricle  on 
each  side  of  the  heart;  the  cavities  on  one  side  being  separated  from  those 
of  the  other  side  by  a  longitudinal  muscular  septum.  The  division  into  4 
cavities  is  indicated  on  the  external  surface  of  the  organ  by  grooves,  named, 
from  their  contiguous  cavities,  the  auricula-ventricular  groove  transversely, 
and  the  inter-ventricular  grooves  longitudinally. 

Structure  of  the  Heart.  The  muscular  fibres  forming  the  heart  take 
origin  from  four  fibrous  rings  at  the  auriculo-ventricular  and  aortic  open- 
ings. The  fibres  of  the  auricles  are  arranged  in  two  layers,  a  superficial 
and  a  deep  one,  the  latter  having  looped  fibres  and  annular  fibres.  In  the 
ventricles  the  fibres  are  also  superficial  and  deep,  the  latter  being  arranged 
circularly,  the  former  spirally,  coiling  inward  at  the  apex  of  the  heart  into  a 
whorl-like  form,  the  vortex. 


THE   HEART 


IIQ 


FIG.  61. 


Vessels  and  Nerves.  The  Arteries  are  the  right  and  left  coronary  from 
theTaorta.  The  Veins  accompany  the  arteries  and  terminate  in  the  right 
auricle.  The  Lymphatics,  terminate  in  the  thoracic  and  right  lymphatic 
ducts.  The  N>  /  are  derived  from  the  cardiac  plexuses,  which  are 
formed  partly  f  vhe  cranial  nerves  and  partly  from  the  sympathetic. 

THE  RIGHT  HEART 

The  Right  Auricle  (atrium  dextrum)  is  slightly  larger  than  the  left,  its 
walls  somewhat  thinner,  being  about  one  line  in  thickness;  its  cavity  con- 
tains about  2  fluidounces.  It  consists  of  two  parts,  a  principal  cavity,  the 
sinus  venosus  (i)  or  atrium, 
situated  posteriorly,  and  a 
smaller  portion,  the  appendix 
auricula  (auricula  dextra)  (2), 
situated  anteriorly.  It  re- 
ceives the  venous  blood  by 
the  superior  (3)  and  inferior 
(4)  venae  cavae  and  the  coro- 
nary sinus,  and  presents  in- 
teriorly the  following  points 
for  examination:— 

Appendix  Auricula  (auric- 
ula dextra)  (n), — a  con- 
ical pouch  projecting  from 
the  sinus  to  the  front  and 
left,  its  margins  being 
dentq,ted. 
Openings — of  the  superior 

and  inferior  venae  cavae  and  the  coronary  sinus  (7),  the  latter  having 
a  valve  in  two  segments. 
foramina   Thebesii  (foramina  venarum  minimarum), — several  minute 

orifices,  the  mouths  of  veins  from  the  substance  of  the  heart. 
Auricula-ventricular  Opening    (ostium  venosum  dextrum)    (9), — com- 
municates with  the  right  ventricle,  is  oval,  about   i%  inch  broad, 
surrounded  by  a  fibrous  ring,  and  is  guarded  by  the  tricuspid  valve. 
Fossa  Ovalis  (5), — a  depression  on  the  inner  wall,  corresponding  to  the 

situation  of  the  foramen  ovale  in  the  foetus. 
Annulus  Ovalis  (limbus  fossae  ovalis  [Vieussenii]), — the  oval  margin  of 

the  fossa  ovalis. 

Musculi  Pectinatij — muscular  columns  on  the  inner  surface  of  the  appen- 
dix and  the  inner  wall  of  the  auricle. 


120  HUMAN    ANATOMY 

Tubercle  of  Lower  (tuberculum  intervenosum  [Lower!]), — a  very  small 
projection  on  the  right  wall,  supposed  to  influence  the  direction  of  the 
blood-current. 

Eustachian  Valve  (valvula  venae  cavae  inferioris  [Eustachii])  (6), — at 
the  anterior  margin  of  the  inferior  vena  cava;  large  in  the  foetus,  to 
direct  the  blood  to  the  foramen  ovale. 

Coronary  Valve  (valvulae  sinus  coronarii  [Thebesii])  (Valve  of  Thebe- 
sius)  (8), — a  semicircular  fold  which  protects  the  orifice  of  the 
coronary  sinus  and  prevents  regurgitation  of  blood  into  the  sinus. 

The  Right  Ventricle  (ventriculus  dexter)  (a)  is  triangular  in  form  and 
extends  from  the  right  auricle  to  near  the  apex  of  the  heart.  Its  anterior 
surface  is  rounded  and  convex  and  forms  the  larger  part  of  the  front  of 
the  heart.  Its  under  surface  is  flattened  and  rests  upon  the  diaphragm. 
Its  cavity  (b  c)  can  contain  about  3  fluidounces,  and  presents  the  following 
points  for  examination: — 

Tricuspid  Valve  (valvula  tricuspidalis)  (e,  /), — consists  of  3  triangular 
segments  connected  by  their  bases  with  the  auriculo-ventricular  ori- 
fice, and  by  their  sides  with  each  other,  the  largest  being  on  the  left 
side. 

Semilunar  Valves  (valvulse  semilunares  a.  pulmonalis)  (m), — are  3  in 
number,  and  guard  the  orifice  of  the  pulmonary  artery;  each  about 
the  middle  of  its  free  margin  has  a  fibrocartilaginous  nodule,  the 
corpus  Arantii  (noduli  valvarum  semilunarum  [Arantii]),  which 
more  perfectly  closes  the  orifice. 

Opening  of  the  Pulmonary  Artery  (ostium  arteriosum  pulmonis), — at  the 
superior  and  internal  angle  of  the  ventricle,  the  conus  artericsus.  It 
is  circular  in  form,  surrounded  by  a  fibrous  ring,  and  is  guarded  by 
three  semilunar  valves. 

Sinuses  of  Valsalva, — are  3  pouches,  one  behind  each  valve,  between  it 
and  the  commencement  of  the  pulmonary  artery. 

Columns  Ccrnece,  (trabeculae  carnae)  (g), — muscular  columns  projecting 
from  the  surface  of  the  ventricle,  of  which  3  or  4,  called  musculi 
papillares,  give  attachment  to  the  chordae  tendinae. 

Chorda  Tending  (1), — delicate  tendinous  cords  which  connect  the  mar- 
gins and  lower  surfaces  of  the  tricuspid  valve  with  the  columnae. 

THE  LEFT  HEART 

The  Left  Auricle  (atrium  sinistrum)  is  smaller  than  the  right,  but  has 
thicker  walls,  being  about  i^  line.  Like  the  right  auricle  it  consists  of  a 
principal  cavity  (i)  or  sinus  (atrium)  and  an  appendix  auricula  (auricula 


THE   HEART 


121 


sinistra,  (2),  which  overlaps  the  root  of  the  pulmonary  artery.     Internally 
the  auricle  presents  the  following  parts: — 

Openings  (3)  of  the  Pulmonary  Veins, — are  4  in  number,  sometimes  3,  as 
the  two  left  veins  (5)  frequently  end  in  a  common  opening.     They 
have  no  valves. 
Left  Auricula-ventricular  Opening  (ostium  venosum  ventriculi  sinistri) 

(6), — is  smaller  than  the  right  one. 

Musculi  Peciinati, — on  the  inner  surface  of  the  appendix. 
Depression, — corresponding  to  the  fossa  ovalis  in  the  right  auricle. 


FIG.  62. 


The  Left  Ventricle  (ventriculus  sin- 
ister) (8)  is  longer,  thicker  and  more 
conical  in  shape  than  the  right  ven- 
tricle (/O,  and  it  forms  a  small  part  of  V- 
the  anterior  surface  of  the  heart  but 
a  considerable  part  of  its  posterior 
surface.  By  its  projection  beyond 
the  apex  of  the  right  ventricle  it 
forms  the  apex  of  the  heart.  Its  walls 
are  the  thickest  of  those  in  the  heart, 
being  thrice  as  thick  as  those  of  the 
right  ventricle.  Its  interior  (9)  pre- 
sents the  following: — 

Left  Auricula-ventricular  Opening 
(ostium  venosum  ventriculi  sin- 
istri),— is  surrounded  by  a  dense 
fibrous  ring  (annulus  fibrosus  sin- 
ister) and  is  guarded  by  the  mitral 
valve  (valvula  bicuspidalis). 
Aortic  Opening  (ostium  arteriosum), — is  small  and  circular,  placed  in 
front  and  to  the  right  of  the  auriculo-ventricular,  a  segment  of  the 
mitral  (bicuspid)  valve  being  between  them.  It  is  surrounded  by  a 
fibrous  ring,  and  guarded  by  the  semilunar  valves  (valvulae  semi- 
lunares  aortae). 

Mitral  Valve  (valvula  bicuspidalis)  (a), — consists  of  two  unequal- 
sized  segments,  and  is  attached  to  the  fibrous  ring  which  surrounds 
the  auriculo-ventricular  opening  (ostium  venosum  ventriculi  sinistri). 
Its  margins  are  connected  with  the  ventricular  walls  by  chordae 
tendinae  and  musculi  papillares. 

Semilunar  Valves  (valvulae  semilunares  aortae), — 3  in  number ggjuard  the 
aortic  orifice,  and  are  larger  and  stronger  than  those  on  the  right  side. 


122  HUMAN   ANATOMY 

Sinus  of  Valsalva, — a  pouch  in  the  wall  of  the  aorta  opposite  each  seg- 
ment of  the  semilunar  valves. 

ColumncB  Carnea  (6), — are  smaller  and  more  numerous  than  those  on 
the  right  side;  the  musculi  papillares  are  but  two  in  number,  one  con- 
nected to  the  anterior,  the  other  to  the  posterior  wall. 


THE  ARTERIES 

The  Arteries  are  cylindrical  tubular  vessels  which  carry  blood  from  the 
ventricles  of  the  heart  to  every  part  of  the  body.  The  Aorta  and  its 
branches,  together  with  the  returning  veins,  constitute  the  greater  or 
systemic  circulation.  The  Pulmonary  Artery  and  its  branches  to  the  lungs, 
together  with  the  returning  veins,  constitute  the  lesser  or  pulmonic  cir- 
culation. The  arteries  anastomose  or  communicate  freely  with  each 
other  everywhere  throughout  the  body,  permitting  the  establishment  of 
collateral  circulations. 

Structure  of  the  Arteries.  They  are  dense  in  structure,  very  elastic, 
preserving  their  cylindrical  form,  and  are  composed  of  3  coats,  an  Internal 
or  serous  (tunica  intima);  a  Middle  (tunica  media),  composed  of  muscular 
and  elastic  tissue;  and  an  External  (tunica  externa  or  adventitia),  com- 
posed of  connective  tissue.  They  are  generally  included  in  a  fibro- 
areolar  investment,  the  Sheath,  which  also  encloses  the  accompanying  veins. 
The  larger  arteries  are  nourished  by  the  Vasa  Vasorum,  blood-vessels 
which  ramify  in  the  external  and  middle  coats;  and  are  supplied  with 
nerves,  the  Vaso-motor,  derived  from  both  the  sympathetic  and  cerebro- 
spinal  systems,  and  forming  intricate  plexuses  on  the  larger  trunks. 

The  Capillaries  are  minute  vessels  forming  a  network  throughout  the 
tissues  of  the  body  between  the  terminating  arteries  and  the  commencing 
veins.  Their  average  diameter  is  about  the  Hooo  of  an  inch,  average 
length  ^o  of  an  inch  and  their  walls  consist  of  a  transparent  homoge- 
neous membrane  continuous  with  the  innermost  layer  of  the  arterial 
and  venous  walls. 

THE  PULMONARY  ARTERY  AND  AORTA 

The  Pulmonary  Artery  (a.  pulmonalis)  alone  of  the  arteries  carries 
venous  blood,  which  it  conveys  from  the  right  side  of  the  heart  to  the 
lungs.  It  is  i^-i  inch  in  diameter  and  only  about  2  inches  long,  and  all 
within  the  pericardium;  arising  from  the  right  ventricle  in  front  of  the 
ascending  aorta,  passing  upward  and  backward  to  the  under  surface  of 
the  arch  of  the  aorta,  where  it  bifurcates,  and  is  connected  at  its  root  to 


THE    AORTA  123 

the  aorta  by  a  fibrous  cord,  the  remains  of  the  ductus  artcriosus  of  the 
foetus.  Its  terminal  branches  are  the — 

Right  (ramus  dexter  a.  pulmonalis)  and  Left  (ramus  sinister  a.  pulmonalis) 
Pulmonary  Arteries, — the  latter  being  tne"  shorter  of  the  two;  they  pass 
horizontally  outward  to  the  roots  of  their  respective  lungs,  where  each 
divides  into  two  branches,  which  again  and  again  subdivide  to  ramify 
throughout  the  lung  tissue  and  end  in  the  capillaries  of  those  organs. 

The  Aorta  (arteria  magna)  is  the  main  trunk  of  the  systemic  arteries, 
commencing  at  the  aortic  opening  of  the  left  ventricle  of  the  heart,  it  arches 
backward  over  the  roof  of  the  left  lung  into  the  thorax,  where  it  descends 
on  the  left  of  the  spinal  column,  and  after  passing  through  the  aortic 
opening  in  the  diaphragm,  it  terminates  in  the  right  and  left  common 
iliac  arteries  opposite  the  4th  lumbar  vertebra.  It  is  divided  into  the 
^Ascending  Aorta  (aorta  asc'ehdens)  (5),  the  Arch  (arcus  aortae)  (6),  and 
the  Ascending  Aorta  (aorta  descendens)  (12),  the  last-named  being  again 
divided  into  the  Thoracic  Aorta  (aorta  thoracalis)  and  the  Abdominal 
Aorta  (aorta  abddnimalis)  (described  under  Arteries  of  the  Trunk). 
Th*e"  upper  border  of  the  arch  is  generally  situated  about  an  inch  below 
the  upper  margin  of  the  sternum.  The  branches  of  the  aorta  are — 

From  the  Ascending  Aorta, — 2  Coronary  Arteries  (4). 

From  the  Arch, — Innominate  (a.  anonyma)  (7).     Left  Common  Carotid 

(10).     Left  Subclavian  (n). 
From  the  Thoracic, — Pericardia!.         (Esophageal.         18  Intercostals. 

Bronchial.  Posterior  Mediastinal. 

From  the  Abdominal,— 2  Phrenic. 

{  Gastric. 
Cceliac  Axis.  {  Hepatic. 

(  Splenic  (a.  lienalis). 

2  Spermatic,  in  the  male. 

2  Ovarian,  in  female.  Inferior  Mesenteric. 

Superior  Mesenteric.  8  Lumbar. 

2  Supra-renal.  Sacra  Media. 

2  Renal.  2  Common  Iliac. 

The  Coronary  Arteries  are  2  in  number,  a  right  and  a  left  (4),  arise  from 
the  aorta  in  the  sinuses  of  Valsalva  behind  the  semilunar  valves,  and  run  in 
the  vertical  grooves  of  the  heart,  the  left  artery  in  front,  to  supply  the 
tissue  of  that  organ.  Each  artery  divides  into  2  branches,  the  transverse 
and  the  descending,  the  latter  anastomosing  at  the  apex  of  the  heart  with 
its  fellow  of  the  opposite  side.  The  descending  branch  of  the  right  coro- 


124 


HUMAN   ANATOMY 


FIG.  63. 


nary  sends  off  a  marginal  branch  along  the  margin  of  the  right  ventricle, 
and  an  infundibular  branch  to  the  conus  ar- 
teriosus  of  the  same  ventricle. 

The  Innominate  Artery  (a.  anonyma)  (7) 
arises  from  the  summit  of  the  arch  of  the 
aorta,  is  i^  inch  long,  and  divides  behind 
the  right  sternoclavicular  joint  into  the  Right 
Common  Carotid  (9)  and  Right  Subdavian  (8), 
these  arteries  on  the  left  side  of  the  body  (10, 
n)  arising  directly  from  the  arch  of  the  aorta. 
It  sometimes  sends  off  a  small  branch,  the 
Thyroidea  ima,  to  the  thyroid  body;  which 
vessel  may  arise  from  the  arch  of  the  aorta, 
the  right  common  carotid,  the  subclavian,  or 
the  internal  mammary.  The  Innominate 
artery  is  sometimes  absent  and  not  infre- 
quently varies  in  length  from  }$  inch  to  2  inches. 

ARTERIES  OF  THE  HEAD  AND  NECK 


The  Common  Carotid  Arteries 

(Arterae  Carotides  Communes). 
Arising  differently  (see  above) 
the  two  carotids  are  similarly 
described,  except  that  the  left 
is  longer  and  deeper  than  the 
right  one.  Their  course  is  indi- 
cated by  a  line  drawn  from  a 
point  midway  between  the 
angle  of  the  lower  jaw  and  the 
mastoid  process  to  the  sterno- 
clavicular articulation.  At  the 
lower  part  of  the  neck  they  are 
separated  only  by  the  width  of 
the  trachea,  and  they  are  each 
contained  in  a  sheath  of  the 
deep  cervical  fascia  with  the 
internal  jugular  vein  externally 
and  the  pneumogastric  nerve 
(n.  vagus)  between  the  artery 
and  vein.  On  the  front  of  the 
sheath  lies  the  descendens  hypo- 


Pic.  64. 


ARTERIES    OF    THE   HEAD   AND    NECK  125 

glossi  nerve  (descending  branch  of  the  i2th  or  hypoglossal).  The 
artery  lies  beneath  the  inner  border  of  the  sterno-cleido-mastoid  muscle, 
and  is  crossed  about  its  middle  by  the  omo-hyoid  muscle  and  the  middle 
thyroid  vein.  It  is  also  crossed  above  by  the  facial,  lingual,  and  su- 
perior thyroid  veins,  below  by  the  anterior  jugular  vein,  and  on  the  left 
side  often  by  the  internal  jugular  vein.  It  bifurcates,  at  the  level  of  the 
upper  border  of  the  thyroid  cartilage,  into  the  External  and  Internal 
Carotids,  of  which  the  internal  is  the  more  remote  from  the  median  line. 

The  External  Carotid  Artery  (a.  carotis  externa)  (2)  (Fig.  64)  commences 
opposite  the  upper  border  of  the  thyroid  cartilage,  and  passes  upward, 
forward  and  backward  to  the  space  between  the  neck  of  the  condyle  of  the 
lower  jaw  and  the  external  meat  us,  where  it  divides  into  the  temporal  and 
internal  maxillary  arteries.  It  has  8  branches,  the — 
Superior  Thyroid  (a.  thyreoidea  superior)  (4), — arising  below  the  greater 

cornu  of  the  hyoid  bone;  giving  off — 

Muscular.         Hyoid.  Superior  Laryngeal. 

Glandular.        Superficial  Descending.  Crico-thyroid. 

Lingual  (a.  lingualis)  (5), — under  the  hyo-glossus  muscle  to  the  tongue; 

giving  off — 

Hyoid.         Dorsalis  Linguae.         Sublingual.         Ranine. 
Facial  (a.  maxillaris  externa),  should  be   called  superficial  facial   (6),— 

crosses    the  lower  jaw  at  the  anterior  border  of  the  masseter;  giving 

off- 
Inferior  (Ascending)  Palatine.     Submental  (7).       2  Coronary  (aa.  la- 

Tonsillar.  Muscular.  biales)  (8,  9). 

Submandibular.  Inferior  Labial.      Lateralis  Nasi. 

Angular. 

Occipital  (a.  occipitalis)  (10), — lies  in  the  occipital  groove  of  the  temporal 
bone. 

Muscular.  Auricular.  Arteria  Princeps  Cervicis 

Sterno-mastoid.  Meningeal.  (13)   (ramus  descen- 

dens  a.  occipitalis). 

Posterior  Auricular  (a.  auricularis  posterior)  (14), — ascends  under  cover  of 

the  parotid  gland. 

Stylo-mastoid.     Auricular.     Mastoid.     Muscular.     Glandular. 
Ascending   Pharyngeal,    (a.    pharyngea  ascendens), — lies  on  the  rectus 
capitis  anticus  major. 

Prevertebral.         Pharyngeal.         Tympanic.         Meningeal. 


126 


HUMAN    ANATOMY 


FIG.  65. 


Superficial  Temporal  (a.  temporalis  superficialis)  (15), — the  smallest  of  the 
termini  of  the  external  carotid,  begins  in  the  parotid  gland,  crosses  the 
zygomatic  arch,  and  divides  into  anterior  (13)  and  posterior  temporal 
(16).  Its  branches  are  the — 

Parotid.     Articular.     Zygomatico-orbital.     Frontal.     Parietal. 
Transverse  Facial  (15).     Middle  Temporal  (17).     Anterior  Auricular. 

Internal  Maxillary  (a.  maxillaris  in- 
terna),  should  be  called  deep  facial 
(4), — the  other  terminal  branch 
of  the  external  carotid  (i),  is  di- 
vided into  three  portions,  Maxil- 
lary (4),  Pterygoid  (5),  and 
Spheno- maxillary  (6),  which  re- 
spectively give  off  the  following 
branches  (Fig.  65): 

Maxillary 

Deep    Auricular,  to  the  tragus 

and  canal. 

Anterior   Tympanic   (7),   enter- 
ing the  Glaserian  (petro-tym- 
panic)  fissure. 
Middle  Meningeal  (8). 
Small  or  Accessory  Meningeal  (9). 
Inferior  Alveolar  or  Dental  (10),  divides  into  Incisor  and  Mental. 


Pterygoid 

Deep  Temporal,  ant.  and  poste- 
rior. 

Pterygoid  Branches,  to  those 
muscles. 

Masseteric,  to  the  masseter  mus- 
cle. 

Buccal,  to  the  buccinator 
muscle. 


S  pheno-maxillary 

Posterior  Superior  Alveolar  (n). 
Infra-orbital  (12). 
Descend.  Palatine  (13). 
Vidian  (a.  canalis  pterygoidea) 

(16). 

Pterygo-palatine  (15). 
Spheno-palatine    or    Naso-paia- 

tine  (14). 
Pharyngeal. 

The  Internal  Carotid  Artery  (a.  carotis  interna)  commences  at  the 
bifurcation  of  the  common  carotid  and  ascends  in  front  of  the  transverse 
processes  of  the  three  upper  cervical  vertebrae,  and  close  to  the  tonsil, 
traverses  the  carotid  canal  in  the  temporal  bone,  and  after  piercing  the 


INTERNAL   CAROTID   ARTERY  127 

dura  mater  close  by  the  anterior  clinoid  process,  divides  into  its  terminal 
(cerebral)  branches.  It  curves  remarkably  in  different  parts  of  its  course, 
in  the  carotid  canal  and  alongside  the  body  of  the  sphenoid  bone  it  de- 
scribes a  double  curvature  resembling  the  italic  letter  S  placed  horizon- 
.  tally.  In  the  cervical  portion  no  branches  are  given  off;  in  the  petrous, 
cavernous  and  cerebral  portions  it  gives  off  the  following: — 

Tympanic   (a.    carotico- tympanic), — enters   the   tympanum  from   the 
carotid  canal,  and  anastomoses  on  the  membrana  tympani  with  the 
tympanic  branch  of  the  internal  maxillary  and  the  stylo-mastoid. 
Arteries  Receptaculi  (aa.  cavernosae), — numerous  small  vessels  going  to 
the  walls  of  the  sinuses,  the  Gasserian  (semilunar)  ganglion  and  the 
pituitary  body  (hypophysis). 
Anterior  Meningeal, — a  small  branch  to  the  dura  mater  of  the  anterior 

fossa,  after  passing  over  the  lesser  wing  of  the  sphenoid. 
Ophthalmic^ — arises  from  the  cavernous  portion,  enters  the  orbit  through 
the  optic  foramen,  terminating  at  the  inner  angle  of  the  eye  into  the 
frontal  and  nasal  branches.     It  gives  off  the  following  branches: — 

Ocular  Group  Orbital  Group 

Art.  Centralis  Retinae.  Lacrimal.  Frontal. 

Muscular.  Supra-orbital.  Nasal. 

Anterior  Ciliary.  Posterior  Ethmoidal.  (the 

Short  Ciliary.  Anterior  Ethmoidal.  terminal. 

Long  Ciliary.  Internal  Palpebral.  branches). 

•'**'  Anterior  Cerebral, — joined  to  its  fellow  by  the  Anterior  Communicating 
Artery,  about  2  lines  long;  then  runs  alongside  its  fellow,  terminating 
by  anastomosis  with  the  posterior  cerebral  arteries,  and  giving  off  the 
following  branches: — 

Antero-median  Ganglionic  or  Basal. 
Inferior  Internal  or  Medial  Frontal. 
Ant.  Internal  or  Medial  Frontal. 
Middle  Internal  or  Medial  Frontal. 
Posterior  Internal  or  Medial  Frontal. 

Middle  Cerebral  (a.  cerebri  media), — in  the  fissure  of  Sylvius;  divides 
into:— 

Antero-lateral  Ganglionic  or  Basal.  Ascending  Frontal. 

Inferior  External  or  Lateral  Frontal.  Ascending  Parietal. 

Parieto-temporal. 

Posterior  Communicating, — anastomoses   with   the  posterior   cerebral, 
a  branch  of  the  basilar,  and  gives  off  the: — 


128  HUMAN    ANATOMY 

Postero-median  Ganglionic,  branches  supplying  the  optic  thalami 

and  the  walls  of  the  3rd  ventricle. 
Anterior  Choroid,—to  the  hippocampus  major,  corpus  fimbriatum,  etc. 

and  ends  in  the  choroid  plexus. 

[The  vertebral  Artery,  a  branch  of  the  Subclavian,  and  the  Basilar  Artery, 
formed  by  the  junction  of  the  two  vertebrals,  may  be  considered  arteries 
of  the  head  and  neck,  but  they  are  most  conveniently  described  as  branches 
of  the  Subclavian  Artery  (see  below.)] 

THE  CIRCLE  OF  WILLIS 

The  Circle  of  Willis  (circulus  arteriosus)  is  a  remarkable  anastomosis 
at  the  base  of  the  brain,  formed  by  the  branches  of  the  vertebral  and  in- 
ternal carotid  arteries,  and  giving  origin  to  the  3  trunks  which  supply 
each  cerebral  hemisphere.  Posteriorly,  the  two  Vertebral  arteries  unite 
to  form  the  Basilar,  which  ends  in  the  two  Posterior  Cerebral.  Anteriorly, 
each  Internal  Carotid  gives  off  the  Anterior  Cerebral,  these  latter  being 
connected  by  the  short  Anterior  Communicating  artery.  The  circle  is 
completed  by  the  Posterior  Communicating  arteries,  one  on  each  side, 
which  connect  the  posterior  cerebral  with  the  internal  carotid. 

The  Circle  of  Willis  gives  off, — anteriorly,  the  anterior  cerebral  arteries; 
antero-laterally,  the  middle  cerebral;  and  posteriorly,  the  posterior  cerebral; 
each  artery  giving  origin  to  two  very  different  arterial  systems:  the  Cen- 
tral Ganglionic  System,  supplying  the  central  ganglia  of  the  brain;  the 
Cortical  Arterial  System,  which  ramifies  the  pia  mater  and  supplies  the 
cortex  and  subjacent  medullary  substance.  The  two  systems,  though 
having  a  common  origin,  do  not  communicate  afterwards,  and  in  their 
distribution  are  entirely  independent  of  each  other.  Hence,  between  the 
parts  supplied  by  each,  there  is  a  zone  of  diminished  nutritive  activity, 
where  softening  may  be  especially  liable  to  occur  in  the  brains  of  old  people. 
By  the  Circle  of  Willis  the  cerebral  circulation  is  equalized  and  provision 
made  for  carrying  it  on  if  one  or  more  of  the  branches  should  be 
obliterated. 

THE  TRIANGLES  OF  THE  NECK 

Anterior  Triangle  of  the  Neck  is  bounded,  in  front,  by  a  line  extending 
from  the  chin  to  the  sternum;  behind,  by  the  anterior  margin  of  the 
sterno-mastoid  muscle;  its  base,  directed  upward,  is  formed  by  the  lower 
border  of  the  body  of  the  jaw  and  a  line  extending  from  the  angle  of  the 
jaw  to  the  mastoid  process;  its  apex  is  below,  at  the  sternum.  It  is 
crossed  by  the  digastric  muscle  above  and  the  anterior  belly  of  the  omo- 
hyoid  below,  dividing  it  into  3  smaller  triangles,  named  from  below  up- 


TRIANGLES    OF   THE   NECK  I  29 

ward  the  Inferior  Carotid,  the  Superior  Carotid,  and  the  Submaxillary 
or  Submandibular  triangles. 

Inferior  Carotid  Triangle,  situated  below  the  anterior  belly  of  the  omo- 
hyoid,  contains  at  it's  posterior  edge  in  a  common  sheath  the  lower  portion 
of  the  common  carotid  artery,  the  pneumogastric  nerve  and  the  internal 
jugular  vein,  concealed  by  the  sterno-mastoid  muscle,  also  other  structures, 
which  with  the  former  may  be  summarized  as  follows: — 
Muscles, — the  sterno-hyoid  and  sterno-thyroid,  covering  the  common 

carotid  artery. 

Arteries, — the  common  carotid  and  the  inferior  thyroid. 
Veins, — the  internal  jugular,  as  described  above. 

Nerves, — the  pneumogastric  (n.  vagus)  recurrent  laryngeal,  and 
sympathetic,  also  filaments  from  the  loop  between  the  descendens  and 
communicans  hypoglossi. 

Other  Structures, — the  trachea,  thyroid  gland,  and  the  lower  part  of  the 
larynx. 

Superior  Carotid  Triangle,  situated  above  the  anterior  belly  of  the  omo- 
hyoid,  contains  the  upper  part  of  the  common  carotid  artery  and  its 
bifurcation  into  the  internal  and  external  carotid,  also  other  structures, 
all  summarized  as  follows: — 

Muscles, — parts  of  the  thyro-hyoid,  hyo-glossus,  inferior  and  middle  con- 
strictors of  the  pharynx. 

Vessels, — the  common  carotid  artery,  the  internal  and  external  carotid 
arteries,  and  the  internal  jugular  vein;  the  superior  thyroid,  lingual, 
facial    (external    maxillary),    occipital    and    ascending    pharyngeal 
branches  of  the  external  carotid  and  the  veins  accompanying  them. 
Nerves, — the  pneumogastric    (n.  vagus),  spinal  accessory  (n.  accesso- 
rius),  hypoglossal,  descendens  hypoglossi,  sympathetic,  internal  and 
external  laryngeal. 
Other  Structures, — the  upper  part  of  the  larynx,  and  the  lower  part  of  the 

pharynx. 

Sub-mandibular  or  Sub-maxillary  Triangle,  immediately  below  the 
body  of  the  jaw,  and  above  the  posterior  belly  of  the  digastric  and  the 
stylo-hyoid;  contains  the  following: — 

Muscles, — the     mylo-hyoid,     hyo-glossus,     stylo-glossus,     and     stylo- 

pharyngeus. 

Arteries, — the  external  and  internal  carotid;  also  the  facial  (external 
maxillary),   posterior   auricular,   temporal,  internal   maxillary,  sub- 
mental,  and  mylo-hyoid  arteries. 
Veins, — the  facial  and  internal  jugular, 
o 


130  HUMAN   ANATOMY 

Nerves, — the  pneumogastric  (n.  vagus),  glosso-pharyngeal,  facial,  and 

mylo-hyoid. 
Glands, — the  parotid  and  sub-maxillary  (sub-mandibular). 

Posterior  Triangle  of  the  Neck  is  bounded,  in  front  by  the  sterno- 
mastoid  muscle;  behind,  by  the  trapezius;  its  base  corresponds  to  the 
middle  third  of  the  clavicle,  its  apex  is  at  the  occiput.  It  is  crossed  by 
the  posterior  belly  of  the  omo-hyoid  muscle  about  an  inch  above  the 
clavicle,  subdividing  it  into  two  smaller  triangles,  the  Occipital  above,  and 
the  Subclavian  below. 

Occipital  Triangle,  the  larger  division  of  the  posterior  triangle  of  the 
neck,  above  the  posterior  belly  of  the  omo-hyoid  muscle,  contains  the 
following: — 

Muscles, — the  splenius,  levator  anguli  scapulae  (m.  levator  scapulae), 

middle  and  posterior  scaleni. 
Vessels, — the  transversalis  colli  artery  and  vein. 
Nerves, — the  spinal  accessory  (n.  accessorius),  and  descending  branches 

of  the  cervical  plexus. 
Glands, — a  chain  of  lymphatic  glands. 

Subclavian  Triangle,  the  smaller  of  the  divisions  of  the  posterior  triangle 
of  the  neck,  situated  below  the  posterior  belly  of  the  omo-hyoid  muscle, 
and  above  the  middle  third  of  the  clavicle,  contains  the  following: — 
Vessels, — the  subclavian  artery,  the  Subclavian  vein  occasionally,  the 
transversalis  colli  and  suprascapular  arteries  (a.  transversa  scapulae), 
and  veins,  the  external  jugular  and  transverse  cervical  veins. 
Nerves, — the  brachial  plexus,  descending  branches  of  the  cervical  plexus. 

nerve  to  the  subclavius  muscle. 
Glands, — a  lymphatic  gland. 

ARTERIES  OF  THE  UPPER  EXTREMITY 

The  Subclavian  Artery  (Arteria  Subclavia)  arises  on  the  right  side  from 
the  innominate,  of  the  left  side  from  the  arch  of  the  aorta,  and  is  divided 
into  3  portions  by  the  scalenus  anticus  muscle,  which  crosses  it  just 
external  to  the  origin  of  the  thyroid  axis,  viz. — the  parts  internal,  behind, 
and  external  to  that  muscle.  At  the  outer  border  of  the  ist  rib,  the  sub- 
clavian becomes  the  Axillary  Artery.  Its  upper  border  is  a  little  above 
the  clavicle,  and  it  is  separated  from  the  subclavian  vein  by  the  scalenus 
anticus  at  its  origin  from  the  first  rib.  Its  branches  are  all  given  from  its 
first  portion,  except  the  Superior  Intercostal,  which  on  the  right  side 
arises  from  the  second  portion.  Its  branches  are  the — 


SUBCLAVIAN    ARTERY 


FIG.  66. 


VERTEBRAL  (a.  vertebralis)  (6), — passing  up  the  neck,  through  the  fora- 
mina in  the  transverse  processes  of  six  cervical  vertebrae,  enters  the 
skull  by  the  foramen  magnum,  where  it  joins  its  fellow  to  form  the 
Basilar  Artery.     Its  branches  are- 
Lateral  Spinal  Branches. 

Muscular  Branches. 

Posterior  Meningeal. 

Anterior  Spinal. 

Posterior  Spinal. 

Posterior  Inferior  Cerebellar. 

Bulbar. 

The  Basilar  (a.  basilaris), — formed 
by  the  junction  of  the  vertebrals, 
gives  off  on  each  side  a  transverse, 
anterior,  and  superior  cerebellar, 
and  ends  in  the  two  posterior  cere- 
bral. (See  Circle  of  Willis,  pages 
151  and  158.) 

THYROID  Axis  (truncus  thyreocervi- 
calis)  (8), — at  once  divides  into  the 
three  following  branches. 

Inferior  Thyroid  (a.  thyreoidea  inferior)  (7), — to  the  thyroid  gland, 
giving  off — 

Inferior  Laryngeal.  CEsophageal  Branches. 

Tracheal.  Muscular.  Ascending  Cervical  (9). 

2  Terminal. 

Suprascapular  (a.  transversa  scapulae)  (12), — to  the  shoulder- joint 
and  the  dorsum  of  the  scapula,  anastomosing  there  with  the  pos- 
terior and  subscapular. 

Transversalis  Colli  (n), — divides  beneath  the  margin  of  thetrapezius 
into — 

Superficial  Cervical  (ramus  ascendens). 
Posterior  Scapular  (ramus  descendens). 

INTERNAL  MAMMARY  (a.  mammaria  interna)  (13), — arises  opposite  the 
thyroid  axis,  descends  behind  the  costal  cartilages,  and  ends  at  the 
6th  interval,  in  the  musculo-phrenic  and  superior  epigastric,  the 
latter  anastomosing  with  the  deep  epigastric  branch  of  the  external 
iliac.  Its  branches  are  the — 


132  HUMAN    ANATOMY 

Comes  Nervi  Phrenici  Paricardiac.  Perforating, 

(pericardiaco-phrenic),       Sternal.  Musculo-phrenic. 

or  Superior  Phrenic.     Anterior  Intercostal.     Superior  Epigastric. 
/     Mediastinal. 

'"  SUPERIOR  INTERCOSTAL  (a.  intercostalis  suprema)  (14), — gives  off 
branches  in  the  intercostal  spaces  to  the  posterior  spinal  muscles 
and  to  the  spinal  cord.  One  branch,  the — 

Profunda  Cervids  (a.  cervicalis  profunda)  (10), — supplies  the  mus- 
cles of  the  back  of  the  neck,  and  anastomoses  with  the  arteria 
princeps  cervicis  (ramus  descendens  a.  occipitalis)  of  the  occipital. 
This  vessel  occasionally  arises  from  the  subclavian  artery. 
1  The  Axillary  Artery  (a.  axillaris)  (5),  the  continuation  of  the  subclavian, 
commences  at  the  outer  border  of  the  first  rib,  and  terminates  at  the  lower 
border  of  the  tendon  of  the  teres  major  muscle,  where  it  becomes  the 
brachial  artery.     The  pectoralis  minor  crosses  it  and  marks  its  division 
into  three  portions, — ist,  above;  2nd  behind,  and  3rd  below  that  muscle. 
The  brachial  plexus  is  in  close  relation  with  the  artery,  surrounding  it  on 
three  sides  in    the    second   portion.     Its  branches  are  7  in  number   as 
follows: — 

Superior  Thoracic  (a.   thoracalis  suprema), — from    the  first  portion; 

supplies  the  pectoral  muscles  and  the  walls  of  the  thorax. 
Acromial    Thoracic   (a.  thoraco-acromialis), — from    the  first    portion; 
divides  into  the — 
Thoracic  (pectoral)  Branches  2  or  3,— to  the  serratus  magnus  (m. 

serratus  anterior)  and  pectorals. 
Acromial  Branches, — to  the  deltoid  muscles. 
Descending  or  Humeral    (deltoid), — to    the  pectoralis   major  and 

deltoid. 

Clavicular, — a  very  small  branch,  to  the  subclavius  muscle. 
Mar  Thoracic, — from  the  second  portion;  to  the  glands  and  theareolar 

tissue  of  the  axilla. 

Long  Thoracic  (a.  thoracalis  lateralis  or  external  mammary), — from 
"  tlie  second  portion;  to  the  serratus  magnus  (m.  serratus  anterior), 

the  pectoral  muscles  and  the  mammary  gland. 

Subscapular  (a.  subscapularis), — from  the  third  portion;  to  the  inferior 
angle  of  the  scapula,  where  it  anastomoses  with  the  long  thoracic, 
the  intercostal  and  the  posterior  scapular  (ramus  descendens  a. 
transversalis  Colli)  arteries.  It  gives  off  small  branches  to  the  del- 
toid and  triceps  muscles,  and  the 

Dorsalis  Scapulae   (a.  circumflexa  scapulae), — a  large  branch,   to 
the  subscapular  fossa  and  the  axillary  border  of  the  scapula. 


ARTERIES  OF  THE  UPPER  EXTREMITY         133 

Posterior  Circumflex  (a.  circumflexa  humeri  posterior), — from  the  third 
portion;  winds  around  the  neck  of  the  humerus  to  the  deltoid  muscle 
and  the  shoulder-joint,  anastomosing  with  the  anterior  circumflex 
and  other  arteries. 

Anterior  Circumflex  (a.  circumflexa  humeri  anterior), — from  the  third 
portion;  winds  around  the  neck  of  the  humerus,  to  the  head  of  that 
bone,  the  deltoid  muscle  and  the  shoulder-joint,  anastomosing  with 
the  posterior  circumflex. 

The  Brachial  Artery  (a.  Brachialis)  is  the  continuation  of  the  axillary 
from  the  lower  margin  of  the  teres  major  tendon  to  its  bifurcation  into  the 
radial  and  ulnar,  which  is  usually  about  half  an  inch  below  the  bend  of  the 
elbow.  The  median  nerve  crosses  it  from  the  outside  to  the  inside  about 
its  middle.  Above  its  bifurcation  it  is  crossed  diagonally  by  the  bicipital 
fascia  (lacertus  fibrosus).  The  basilic  vein  lies  on  its  inner  side  but  sepa- 
rated from  it  in  the  lower  part  of  the  arm  by  the  deep  fascia.  Its  branches 
are  the — 

Superior  Profunda  (a.  profunda  brachii), — winds  over  the  arm  in  the 
spiral  groove  (sulcus  radialis),  giving  off  the  posterior  articular  to 
the  elbow  anastomosis,  and  a  branch  to  anastomose  with  the  recur- 
rent branch  of  the  radial,  and  a  nutrient  artery  to  the  bone.  This 
artery  supplies  the  triceps  muscle. 

Nutrient  Branch, — enters  the  nutrient  canal  of  the  humerus. 
Inferior  Profunda  (a.  collateralis  ulnaris  superior), — to  the  elbow-joint 

anastomosis. 

-  Anastomotica  Magna    (a.  collateralis     ulnaris   inferior], — anastomoses 
with  the  posterior  articular,   inferior   profunda  (superior  ulnar  col- 
lateral) anterior  and  posterior  ulnar  recurrent. 
Muscular  Branches, — to  the  muscles  in  the  course  of  the  artery. 

The  Radial  Artery  (a.  radialis)  extends  from  the  bifurcation  of  the 
brachial  to  the  deep  palmar  arch,  and  gives  off  the  following  branches: — 
In  the  Forearm, — 

Radial  Recurrent, — to  the  supinators,  the  brachialis  anticus  and  the 
elbow  joint,  anastomosing  with  the  terminal  branches  of  the  superior 
profunda  (a.  profunda  brachii). 

*'-  Muscular  Branches, — to  the  muscles  on  the  radial  side  of  the  forearm. 
Anterior  Carpal  (ramus  carpeus  volaris), — anastomoses  with  the  anterior 
carpal  of  the  ulnar  artery,  forming  the  Anterior  Carpal  Arch  (rete 
carpi  volare). 
Superficialis  Voice, — to  the  muscles  of  the  thumb. 


134  HUMAN    ANATOMY 

In  the  Wrist,— 

Posterior  Carpal  (ramus  carpeus  dorsalis), — anastomoses  with  the  pos- 
terior carpal  of  the  ulnar  artery  forming  the  Posterior  Carpal  Arch 
(rete  carpi  dorsale). 

Metacarpal, — the  first  dorsal  interosseous  branch,  divides  into  two 
dorsal  digital  branches,  supplying  the  adjoining  sides  of  the  index 
and  middle  fingers. 

7      Dor  sales  Pollicis  2, — along  the  sides  of  the  thumb. 
Dorsalis  Indicis, — along  the  radial  side  of  the  index  finger. 
Ln  the  Hand, — 

Princeps  Pollicis, — along  the  sides  of  the  palmar  aspect  of  the  thumb  by 
two  branches  forming  an  arch. 

Radialis  Indicis  (a.  volaris  indicis  radialis), — along  the  radial  side  of 
the  index  finger  to  anastomose  with  the  collateral  digital  and  the 
princeps  pollicis,  giving  a  communicating  branch  to  the  superficial 
palmar  arch  (arcus  volaris  superficialis). 

Perforating  3, — backward  from  the  deep  palmar  arch  to  anastomose 
with  the  dorsal  interosseous  arteries. 

Palmar  Interosseous  3  or  4, — from  the  deep  palmar  arch,  on  the  inter- 
ossei  muscles  to  anastomose  with  the  digital  branches  of  the  super- 
ficial arch  (arcus  volaris  superficialis). 

Palmar  Recurrent, — from  the  deep  palmar  arch  to  the  carpal  joints, 
anastomosing  with  the  anterior  carpal  arch  (rete  carpi  volare). 

The  Ulnar  Artery  (a.  ulnaris)  extends  from  the  bifurcation  of  the 
brachial  just  below  the  bend  of  the  elbow  along  the  ulnar  border  of  the 
forearm  to  the  wrist.  Immediately  beyond  the  pisiform  bone  it  divides 
into  two  branches  which  enter  into  the  formation  of  the  superficial  and 
deep  palmar  (volar)  arches.  Its  branches  are  as  follows: — 
In  the  Forearm, — 

Anterior  Ulnar  Recurrent  (a.  recurrentes  ulnaris  anterior), — anastomoses 
in  front  of  the  inner  condyle  of  the  humerus  with  the  anastomotica 
magna  (inferior  ulnar  collateral)  and  the  inferior  profunda  (superior 
ulnar  collateral). 

Posterior  Ulnar  Recurrent  (a.  recurrentes  ulnaris  posterior), — anasto- 
moses behind  the  inner  condyle  of  the  humerus  with  the  anastomotica 
magna  (inferior  ulnar  collateral),  inferior  profunda  (superior  ulnar 
collateral)  and  interosseous  recurrent. 

Interosseous, — about  %  inch  long,  divides  into  two  branches.  The 
Anterior  Interosseous  (volar  interosseous)  gives  off  the  Median 
Artery  to  the  median  nerve  and  a  Nutrient  branch  to  both  bones  of  the 


ARTERIES    OF    THE    FOREARM    AND   HAND  135 

forearm.     The  Posterior  (dorsal)  Interosseous  gives  off  near  its  origin 
the  Interosseous  Recurrent  to  the  elbow-joint  anastomosis. 

Muscular,—-  to  the  muscles  on  the  ulnar  side  of  the  forearm. 
In  the  Wrist, — 

Anterior  Carpal,  (ramus  carpeus  volaris), — anastomoses  with  a  cor- 
responding branch  of  the  radial  artery  in  front  of  the  carpus. 

Posterior  Carpal  (ramus  carpeus  dorsalis), — anastomoses  with  a  cor- 
responding branch  of  the  radial  artery  forming  the  posterior  carpal 
arch  (rete  carpi  dorsale). 
In  the  Hand, — 

Deep  or  Communicating  (ramus  volaris  profunda), — anastomoses  with 
the  termination  of  the  radial  artery,  completing  the  deep  palmar 
arch  (arcus  volaris  profundus). 

Superficial  Palmar  Arch  (arcus  volaris  superficialis), — is  the  continua- 
tion of  the  trunk  of  the  ulnar  artery  in  the  hand. 

Digital  4, — given  off  by   the  superficial   palmar  arch   (arcus  volaris 

"superficialis). 
-  S  V  THE  CARPAL  ARCHES 

The  Anterior  Carpal  Arch  (rete  carpi  volare)  is  formed  by  the  anastomo- 
sis of  the  anterior  carpal  of  the  radial  with  the  anterior  (volar)  carpal 
of  the  ulnar  artery  in  front  of  the  wrist.  It  is  joined  by  branches 
from  the  anterior  (volar)  interosseous  above  and  by  recurrent  branches 
from  the  deep  palmar  (volar)  arch  below,  and  gives  off  branches  to 
supply  the  articulations  of  the  wrist  and  carpus. 

The  Posterior  Carpal  Arch  (rete  carpi  dorsale)  is  formed  by  the 
anastomosis  of  the  posterior  (dorsal)  carpal  of  the  radial  with  the  posterior 
(dorsal)  carpal  of  the  ulnar  artery.  It  is  joined  by  the  termination  of  the 
anterior  (volar)  interosseous  artery  and  gives  off  dorsal  interosseous 
arteries  for  the  third  and  fourth  interosseous  spaces,  which  divide  into 
dorsal  digital  branches  which  supply  the  adjacent  sides  of  the  middle, 
ring  and  little  fingers,  and  communicate  with  the  digital  arteries  of  the 
superficial  palmar  (volar)  arch,  and  at  their  origin  with  the  perforating 
branches  from  the  deep  palmar  (volar)  arch. 

THE  PALMAR  ARCHES 

The  Superficial  Palmar  Arch  (arcus  volaris  superficialis)  is  formed  by 
the  part  of  the  ulnar  artery  which  lies  in  the  palm  of  the  hand,  and  is 
completed  by  that  artery  anastomosing  with  a  branch  from  theradialis 
indicis,  at  the  root  of  the  thumb;  sometimes  with  the  superficialis  volae 
or  the  princeps  pollicis  of  the  radial.  It  gives  off  4  Digital  Collateral 


136  HUMAN   ANATOMY 

branches  to  the  sides  of  the  fingers,  except  the  radial  side  of  the  index 
finger,  which  with  the  thumb  is  supplied  from  the  radial  artery. 

The  Deep  Palmar  Arch  (arcus  volaris  profundus)  is  formed  by  the 
palmar  portion  of  the  radial  artery,  and  is  completed  by  the  anastomosis  of 
that  artery  with  the  deep  palmar  (communicating)  branch  of  the  ulnar. 
It  lies  upon  the  carpal  ends  of  the  metacarpal  bones  and  the  interossei 
muscles,  about  ^  inch  nearer  to  the  carpus  than  the  superficial  palmar 
(volar)  arch,  from  which  it  is  separated  by  the  transverse  carpal  ligament, 
the  flexor  brevis  minimi  digiti,  (m.  flexor  digiti  quinti  brevis)  the  super- 
ficial flexor  tendons  and  divisions  of  the  median  and  ulnar  nerves.  From 
it  are  given  off  the  radialis  indicis,  palmar  (volar)  interosseous,  perforating 
and  palmar  (volar)  recurrent  branches  of  the  radial  artery. 

ARTERIES     OF    THE    TRUNK 
THE  DESCENDING  AORTA  (AORTA  DESCENDENS) 

The  Descending  Aorta  is  divided  into  two  portions,  the  Thoracic  Aorta 
(aorta  thoracalis)  and  the  Abdominal  Aorta  (aorta  abdominalis),  cor- 
responding to  the  two  great  cavities  of  the  trunk  in  which  they  are 
situated. 

The  Thoracic  Aorta  (aorta  thoracalis)  commences  at  the  lower  border  of 
the  4th  thoracic  vertebra  on  the  left  of  the  spine,  and  descends  in  the  back 
part  of  the  posterior  mediastinum,  terminating  at  the  aortic  opening  in  the 
diaphragm  directly  in  front  of  the  lower  border  of  the  last  thoracic  vertebra. 
Its  branches  are — 

Pericardia!, — irregular  in  origin,  to  the  pericardium. 
Bronchial, — vary  in  number  and  origin;  generally  one  on  the  right  side 
and  two  on  the  left.     They  nourish  the  lungs,  bronchial  glands  and 
the  oesophagus. 
(Esqpjiageal,  4  or  5, — anastomose  on  the  oesophagus  with  branches  of  the 

inferiorThyroid,  phrenic,  and  gastric  arteries. 
Posterior  Mediastinal, — numerous  small  vessels  supplying  the  glands  and 

the  areolar  tissue  in  the  mediastinum. 

Intercostals, — usuallvjj  on  each  side,  the  two  superior  intercostal  spaces 
being  supplied  by  the  superior  intercostal  branch  of  the  subclavian. 
They  run  between  the  two  layers  of  intercostal  muscles,  anastomose 
with  the  anterior  intercostal  branches  of  the  internal  mammary,  and 
each  gives  off  the  following  branches: — 

Posterior  or  Dorsal, — to  the  muscles  and  skin  of  the  back. 

Spinal, — to  the  spinal  cord  and  its  membranes. 

Collateral  Intercostal, — along  the  upper  border  of  the  rib  below. 


ABDOMINAL   AORTA 


137 


FIG.  67. 


.The  Abdominal  Aorta  (aorta  abdominalis)  begins  where  the  thoracic 
aorta  ends  (see  p.  123)  and  terminates  on  the  body  of  the  4th  lumbar 
vertebra,  where  it  divides  into  the  two  common  iliac  arteries.  Its  branches 
are  as  follows: — 

2  Inferior  Phrenic  (i), — one  on  each  side,  but  usually  only  one  arises 
from  the  aorta,  the  other  springing  from  either  the  coeliac  axis  or  the 
renal  artery.  They  go  to  the  under  surface  of  the  diaphragm,  where 
each  a rtery  divides  into  two 
branches,  an  external  and  an  in- 
ternal, the  former  to  the  side  the 
latter  to  the  front  of  the  thorax 
and  the  diaphragm. 
CCELIAC  Axis  (a.  coeliaca)  (2),  arises 
from  the  aorta,  close  to  the  margin 
of  the  opening  in  the  diaphragm, 
runs  forward  for  half  an  inch,  and 
divides  into  the  Left  Gastric,  He- 
patic, and  Splenic  (a.  lienalis)  arte- 
ries, occasionally  giving  off  one  of 
the  phrenics.  The — 
Js'ft  Gastric  (a.  gastrica  sinistra)  (3), 
— supplies  the  stomach  along  its 
lesser  curvature,  anastomosing 
with  the  aortic  cesophageal,  splenic 
(a  lienalis),  and  hepatic  branches. 
JIe£atic  (a.  hepatica)  (4), — forms  the 
lower  boundary  of  the  foramen  of 
Winslow  (foramen  epiploicum), 
passes  upward  to  the  transverse 
fissure  (porta  hepatis)  of  the  liver 
where  it  divides  into  two  branches, 
right  and  left,  supplying  the  corre- 
sponding lobes  of  that  organ.  Its 
branches  are  the — 

Pyloric  (a.  gastrica  dextra), — to 
the  pyloric  end  of  the  stomach 
and  along  the  lesser  curvature 
of  that  viscus. 

Gastro-duodenalis, — giving  off  the  Gastro-epiploica  Dextra  along 
the  greater  curvature  of  the  stomach,  and  the  Pancreatico-duo- 


138  HUMAN   ANATOMY 

denalis  Superior  to  the  contiguous  margins  of  the  duodenum  and 
pancreas. 
Right  Hepatic,  —  to  the  right  lobe  of  the  liver,  giving  off  the  Cystic 

Artery  to  the  gall-bladder. 
Left  Hepatic,  —  to  the  left  lobe  of  the  liver. 

Splenic  (a.  lienalis)  (5),  —  the  largest,  branch  of  the  cceliac  axis,  passes  by 
^""a  very  tortuous  course  to  the  spleen,  giving  off  the  following:  — 

Pancreaticae  Parvae.         Gastric  (VasaBrevia)  (a.a.  gastricae  breves) 

to  the  stomach. 
Pancreatica  Magna.        Gastro-epiploica  Sinistra,  to  the  stomach. 

Terminal  Branches,  enter  the  hilum  of  the  spleen. 

Superior  Mewnteric  (a.  mesenterica  superior)  (9),  —  supplies  the  small 
intestine,  caecum,  ascending  and  transverse  colon.  Arising  about 
%  inch  below  the  cceliac  axis  it  arches  forward,  downward,  and  to 
the  left,  giving  off  the  — 

Inferior  Pancreatico-duodenal.          Ileo-colic. 
Vasa  Intestini  Tenuis  (aa.  in-         Colica  Dextra  and  Media. 
testinales),  12  to  15. 

V0"  Supra-renal  (a.  supra-renalis  media)  (6),  —  arise  one  on  each  side, 
opposite  the  origin  of  the  superior  mesenteric,  passing  to  the  supra- 
renal capsules. 

2  Renal  (aa.  renales)  (7),  —  one  from  each  side,  just  below  the  preceding, 
pass  to  the  kidney,  at  its  hilum  having  the  middle  place  between  the 
ureter  behind  and  the  renal  vein  in  front.  U.  A.  V.  (you  'ave!)  • 

2  Spermatic  (aa.  spermaticae  internae)  (10),  —  one  on  each  side,  in  the  male 
through  the  inguinal  canal  to  the  testes;  in  the  female  it  is  called 
Ovarian  (a.  ovarica),  going  to  the  ovaries,  uterus  and  skin  of  the 
labia  and  groins. 

Inferior  Mesenteric  (a  mesenterica  inferior)  (n),  —  supplies  the  descend- 
ing colon,  sigmoid  flexure,  and  most  of  the  rectum,  giving  off  the 
following  branches:  — 

Colica  Sinistra.         Sigmoid  (aa.  sig-         Superior  Hemorrhoidal. 
moidece). 

Lumbar  (aa.  lumbales)  (8),  —  usually  4  on  each  side,  analogous  to  the 
intercostals.  They  each  divide  into  two  branches,  the  — 

Dorsal,  giving  off  a  spinal  branch.         Abdominal. 
Middle  Sacral  (a.  sacralis  media)  (12),  —  arises  just  at  the  bifurcation  of 


/ 


THE  ILIAC   ARTERIES  139 

the  aorta;  it  descends  along  the  last  lumbar  vertebra  and  the  front 
of  the  sacrum  to  the  upper  part  of  the  coccyx,  giving  off  numerous 
branches  on  each  side  to  anastomose  with  the  lateral  sacral  arteries. 
It  terminates  in  a  minute  branch  which  goes  to  the  coccygeal  gland 
(Luschka),  and  sends  off  branches  to  the  rectum. 

THE  ILIAC  ARTERIES  (ARTERLE  ILIAC.E) 

The  Common  Iliac  Arteries  (aa.  iliacae  communes)  extend  from  the 
bifurcation  of  the  aorta  at  the  4th  lumbar  vertebra  to  the  lumbo-sacral 
articulation,  where  each  divides  into  the  External  Iliac  (15)  and  the 
Internal  Iliac  (a.  hypogastrica)  (14);  the  former  supplying  the  lower 
extremity,  the  latter  going  to  the  viscera  and  walls  of  the  pelvis.  The 
common  iliac  arteries  are  about  2  inches  in  length,  the  right  being  a  little 
longer  than  the  left,  and  each  is  crossed  by  the  ureter,  just  before  its 
bifurcation. 

The  Internal  Iliac  (arteria  hypogastrica)  (14)  is  about  i%  inches  long, 
extending  from  the  lumbo-sacral  articulation  to  the  great  sacro-sciatic 
notch,  where  it  divides  into  an  anterior  and  a  posterior  trunk.  From  the 
Anterior  Trunk  are  given  off,  from  above  downward,  the — 

Superior  Vesical  (a.  vesicalis  superior), — the  remaining  previous  part, 
of  the  fcEtal  hypogastric  artery.  It  sends  branches  to  the  bladder 
the  vas  deferens  and  the  ureter;  and  one,  the  Middle  Vesical,  to  the 
base  of  the  bladder. 

Obturator  (a.  obturatoria), — through  the  canal  in  the  obturator  mem- 
brane to  the  thigh,  where  it  divides  into  an  internal  and  external 
branch.  Within  the  pelvis  it  gives  off  an  iliac,  a  vesical,  and  a  pubic 
branch.  In  one  out  of  every  3^  cases  this  artery  arises  from  the 
deep  epigastric  (a.  epigastrica  inferior),  in  2  out  of  every  3  from  the 
internal  iliac  (a.  hypogastrica),  in  i  out  of  7^  by  two  roots  from  both 
vessels  and  in  about  the  same  proportion  from  the  external  iliac. 
Inferior  Vesical  (a.  vesicalis  inferior), — to  the  bladder,  prostrate  gland, 
and  vesiculae  seminales.  In  the  female  this  artery  is  called  the 
Vaginal  (a.  vaginalis). 
Middle  Hemorrhoidal  (a.  haemorrhoidalis  medialis), — to  the  anus  and 

parts  outside  the  rectum. 

Uterine  (a.  uterina), — in   the   female,   anastomosing   with   a  branch 

(ramus  ovarii)  from  the  ovarian.     It  gives  off  cervical  branches  to 

the  cervix  uteri  and  the  azygos  arteries  of  the  vagina. 

Internal  Pudic   (a.   pudenda  interna), — the  smaller  of   the  terminal 

branches  of  the  anterior  trunk,  supplies  the  external   generative 


140  HUMAN    ANATOMY 

organs.     Its  muscular  branches  in  the  pelvis  are  numerous  and  small; 
in  the  perineum  they  are  the — 

Inferior  Hemorrhoidal  (a.         Artery    of     the     Bulb    (a.    bulbi 

haemorrhoidalis  inferior).  urethrae). 

Superficial     Perineal     (a.         Urethral  (a.  urethralis). 

perinei).  Artery  of  the  Corpus  Cavernosum 

Transverse     Perineal     (a.  (a.  profunda  penis). 

trans  versa  perinei).  Dorsal  Artery  of  the  Penis  (a  dor- 

salis  penis). 

Sciatic  (a.  glutaea), — the  other  terminal  branch,  supplies  the  muscles  on 
the  back  of  the  pelvis.     Its  branches  are  the — 
Muscular  (internal),  rami  musculares. 
Hemorrhoidal  Brs. 
Vesical  Branches. 
Coccygeal. 
Cutaneous. 

Comes  Nervi  Ischiadici,  (a.  comitans  n.  ischiadici). 
Muscular  (ext.),  (rami  musculares). 
Anastomotic. 
Articular. 
THE  POSTERIOR  TRUNK  gives  off  the  following: — 

Ilio-lumbar   (a.  ilio-lumbalis), — dividing  into  a  lumbar  and  an  ilica 

branch. 
Lateral  Sacral  (arteriae  sacrales  laterales), — superior  and  inferior  on  each 

side. 

Gluteal  (a.  glutaea  superior), — the  continuation  of  the  posterior  trunk, 
divides  into  a  superficial  and  a  deep  branch,  to  the  glutei  muscles, 
the  skin  over  the  sacrum,  and  the  hip-joint.     Before  dividing  it  gives 
a  nutrient  branch  to  the  ilium,  and  some  muscular  branches. 
The  External  Iliac  (a.  iliaca  externa)  extends  to  beneath  the  centre  of 
Poupart's  ligament  (l.inguinale),  where  it  enters  the  thigh  and  becomes  the 
Femoral  Artery;  lying  between  the  femoral  vein  on  the  inside  and  the 
anterior  crural  nerve  (n.  femoralis)  on  the  outside — V.A.N.     Its  branches 
are  small  muscular  and  glandular,  and  the — - 

Deep  Epigastric  (a.  epigastrica  inferior), — which  arises  a  few  lines  above 
Poupart's  inguinal  ligament,  passes  between  the  peritoneum  and  the 
transversalis  fascia,  to  the  sheath  of  the  rectus  which  it  enters 
and  ascends  behind  that  muscle,  to  anastomose  by  numerous  branches 
with  the  terminal  branches  of  the  internal  mammary  and  inferior 
intercostal.  It  gives  off  the — 


THE    FEMORAL   ARTERY  141 

Cremasteric  (a.  spermaticainthe  male;  a.  ligament!  teres  uteri  in 

the  female). 

Pubic.  Muscular  Branches  (rami  musculares). 

Deep  Circumflex  Iliac  (a.  circumflexa  ilium  profunda), — arises  opposite 
to  the  epigastric,  passes  along  the  crest  of  the  ilium  to  about  its 
middle,  where  it  pierces  the  transversalis  and  runs  backward  between 
that  muscle  and  the  internal  oblique  to  anastomose  with  the  ilio- 
lumbar,  gluteal  (a.  glutaea  superior),  lumbar  and  epigastric  ateries. 

^'5*4       ARTERIES  OF  THE  LOWER  EXTREMITY 

The  Femoral  Artery  (arteria  femoralis)  extends  from  Poupart's  liga- 
ment (1.  inguinale)  to  the  opening  in  the  adductor  magnus,  where  it 
becomes  the  popliteal  artery.  Its  course  corresponds  to  a  line  drawn 
from  a  point  midway  between  the  anterior  superior  spine  of  the  ilium  and 
the  spine  of  pubis,  to  the  inner  side  of  the  inner  condyle  of  the  femur. 
It  lies  in  a  strong  fibrous  sheath  with  the  femoral  vein,  but  divided  from 
the  latter  by  a  fibrous  partition.  It  may  be  divided  into  two  portions, 
the  Common  Femoral  and  the  Superficial  Femoral,  for  convenient  de- 
scription, as  follows: — 

The  Common  Femoral  Artery, — about  2  inches  long,  is  very  superficial, 
rests  on  the  inner  margin  of  the  psoas  muscle,  which  separates  it  from 
the  capsular  ligament  of  the  hip-joint,  and  is  covered  by  the  skin, 
superficial  fascia,  superficial  inguinal  glands,  iliac  portion  of  the  fascia 
lata,  and  the  anterior  part  of  the  sheath  of  the  vessels. 
The  Superficial  Femoral  Artery, — is  only  superficial  in  Scarpa's  triangle 
(femoral  trigone),  being  deeper  in  Hunter's  canal  (adductor  canal). 
It  lies  above  on  the  femoral  vein  and  the  profunda  artery  and  vein; 
below,  on  the  adductor  longus  and  adductor  magnus  muscles.     The 
internal  saphenous  nerve  crosses  it  from  without  inward. 
Branches  of  the  Femoral  Artery,  are  as  follows: — 
Superficial  Epigastric   (a.   epigastrica  superficialis)    (c), — through   the 
saphenous  opening  (fossa  ovalis)  to  ascend  on  the  abdomen,  giving 
off   branches  to  the  skin,  the  superficial  fascia  and  the  superficial 
inguinal  glands. 

Superficial  Circumflex  Iliac  (a.  circumflexa  ilium  superficialis)  (;'), — to 
the  crest  of  the  ilium,  supplying  the  skin  of  the  groin,  the  superficial 
fascia,  and  the  superficial  inguinal  glands. 

Superficial  External  Pudic  (a.  pudenda  externa  superficialis)  (d),— 
through  the  saphenous  opening  (fossa  ovalis)  to  the  skin  of  the 
abdomen,  the  penis  and  the  scrotum  (and  the  labium  in  the  female). 


142 


HUMAN   ANATOMY 


FIG.  68. 


Deep  External  Pudic  (a.  pundenda  externa  profunda)  (d),  to  the  skin  of 

the  scrotum  and  perinseum  (and  the  labium  in  the  female). 
Muscular  (rami  musculares). 

Profunda  Femoris  (Deep  Femoral  Artery)  (e), — arises  posteriorly  about 
i  or  2  inches  below  Poupart's  (inguinal)  ligament,  and  descends  to 
the  lower  third  of  the  back  of  the  thigh,  giving  off  the  following 
branches: — 

Ext.  Circumflex  (a.  circumflexa  femoris 

lateralis)  (g). 
Int.  Circumflex  (a.  circumflexa  femoris 

medialis)  (/). 

3  Perforating  (aa.  perforantes)  (h). 
Terminal  or  4th  perforating. 
Muscular  Branches  (rami  musculares)  (&), — 

to  the  sartorius  and  vastus  internus. 
Anastomotica  Magna  (a.  genu  suprema), — 
arises  from  the  femoral  in  Hunter's  (ad- 
ductor) canal  and  divides  into  a  super- 
ficial and  a  deep  branch,  the  latter  anas- 
tomosing around  the  knee-joint  with  the 
superior  external  and  internal  articular 
arteries,  and  the  recurrent  branch  of  the 
aniecior  tibial. 

Scarpa's  Triangle  (Trigonum  Femorale)  is 
a  triangular  space  in  the  thigh  which  cor- 
responds to  the  depression  seen  immediately 
below  the  fold  of  the  groin.  Its  apex  is  down- 
ward, its  base  formed  by  Poupart's  (inguinal) 
ligament,  and  its  sides  externally  by  the  sar- 
torious,  internally  by  the  adductor  longus. 
Its  floor  is  formed  by  the  iliacus,  psoas,  pec- 
tineus  and  adductor  longus  muscles,  from 
without  inward.  It  is  bisected  vertically  by 

the  femoral  vessels,  which  extend  from  the  middle  of  its  base  to  its  apex. 
It  also  contains  the  anterior  crural  nerve  (n.  femoralis)  external  to  the 
vessels,  together  with  lymphatic  vessels  and  glands  and  some  fat. 

Hunter's  Canal  (Canalis  Adductorius)  is  the  interval  between  the  ad- 
ductor magnus  and  the  vastus  internus  (m.  vastus  medialis)  in  the  middle 
third  of  the  thigh,  extending  from  the  apex  of  Scarpa's  triangle  to  the 
femoral  opening  in  the  adductor  magnus  muscle,  and  lying  beneath  the 


ARTERIES    OF    THE    LEG  143 

sartorius.  It  contains  the  femoral  vessels  in  their  sheath,  the  vein  lying 
behind  and  to  the  outer  side  of  the  artery;  also  the  long  saphenous  nerve,  at 
first  external  to  and  then  in  front  of  the  vessels. 

The  Popliteal  Artery  (a.  Poplitea),  the  continuation  of  the  femoral, 
extends  from  the  opening  in  the  adductor  magnus,  passing  behind  the 
knee-joint,  to  the  lower  border  of  the  popliteus  muscle,  where  it  divides  into 
the  Anterior  and  Posterior  Tibial  Arteries.  It  is  crossed  by  the  popliteal 
vein  and  the  internal  popliteal  nerve  (n.  tibialis),  and  gives  off  the  follow- 
ing-named branches,  which  are  distributed  around  the  knee-joint  in  a  free 
anastomosis;  except  the  Azygos  Articular,  which  pierces  the  posterior 
ligament  of  the  joint  to  reach  the  internal  ligaments  and  the  synovial 
membrane.  Branches  are  named  as  follows: — 
i  Superior  Muscular  Branches. 

Inferior  Muscular,  or  Sural. 

Cutaneous  Branches. 

Superior  Articular,  internal    (a.  genu  superior  medialis)  and    external 
(a.  genu  superior  lateralis). 

Azygos  Articular  (a.  genu  media). 

Inferior  Articular,   internal    (a.   genu  inferior   medialis)   and  external 
(a.  genu  inferior  lateralis). 

The  Anterior  Tibial  Artery  (a.  Tibialis  anterior)  extends  from  the 
bifurcation  of  the  popliteal  to  the  front  of  the  ankle-joint,  where  it  be- 
comes the  Dorsal  is  Pedis.  It  passes  between  the  two  heads  of  the  tibialis 
posticus  (m.  tibialis  posterior)  over  the  upper  edge  of  the  interosseous 
membrane  and  along  its  anterior  surface,  resting  on  the  tibia  for  its  lower 
third.  It  is  accompanied  by  the  anterior  tibial  nerve  (n.  peronaeus  pro- 
fundus)  close  to  it  externally,  and  is  crossed  below  by  the  tendon  of  the 
extensor  proprius  hallucis.  Its  branches  are  named  the — 

Posterior  Recurrent  Tibial  (a.  recurrens  tibialis  posterior). 

Superior  Fibular. 

Anterior  Recurrent  Tibial  (a.  recurrens  tibialis  anterior). 
^  Muscular  (rami  musculares). 

Internal  Malleolar  (a.  malleolaris  anterior  medialis). 

External  Malleolar  (a.  malleolaris  anterior  lateralis). 

The  Dorsalis  Pedis  Artery,  the  continuation  of  the  anterior  tibial,  ex- 
tends from  the  front  of  the  ankle-joint  along  the  tibial  side  of  the  foot,  to 
the  back  part  of  the  ist  intermetatarsal  space,  where  it  terminates  in  the 
Dorsalis  Hallucis  and  the  Communicating  (ramus  plantaris  profundus). 
The  anterior  tibial  nerve  lies  close  to  its  outer  side.  Its  branches  are  as 
follows: — 


144  HUMAN    ANATOMY 

*    Tarsal  (a.  tarsalis  lateralis), — passing  outward  along  the  tarsus. 
-•)    Metatarsal    (a.  arcuata), — giving  off  3   Interosseous    (aa.   metatarseae 

dorsales),  and  the  7  Digital  branched  (aa.  digitales  dorsales). 
Dorsalis  Hallucis, — to  the  great  toe  and  the  inner  side  of  the  second  toe 

by  its  3  digital  branches. 
;    Communicating  (ramus  plantaris  profundus), — dips  down  into  the  sole 

of  the  foot  in  the  ist  interosseous  space  of  the  metatarsus,  to  inosculate 

with  the  external  plantar,  completing  the  plantar  arch.     Its  plantar 

digital  branch,  the  arteria  magna  hallucis,  supplies  the  inner  side 

of  the  great  toe  and  the  adjacent  sides  of  the  great  and  second  toes, 

on  their  plantar  surfaces. 

The  Posterior  Tibial  Artery  (A.  Tibialis  Posterior)  is  a  large  vessel, 
extending  from  the  bifurcation  of  the  popliteal  along  the  back  of  the  tibia 
to  the  fossa  below  the  inner  malleolus,  where  it  divides  into  the  Internal 
(medial)  and  External  (lateral)  Plantar.  The  posterior  tibial  nerve  crosses 
it  a  short  way  below  its  origin  and  then  lies  near  its  outer  side  for  the  rest 
of  its  course.  Its  branches  are  as  follows: — 
/  Peroneal  (a.  peronaea) , — along  the  fibular  side,  giving  off  the  following : — 

Muscular  (rami  musculares). 

Nutrient  of  the  fibula  (a.  nutrica  fibulae). 

Anterior  Peroneal  (ramus  perforans). 

Communicating  (ramus  communicans). 

Posterior  Peroneal. 

External  Calcanean  (ramus  calcaneus  lateralis). 
Nutrient  of  the  Tibia  (a.  nutrica  tibiae), — the  largest  nutrient  artery  of 

bone  in  the  body. 
Muscular  Branches  (rami  musculares), — to  the  posterior  muscles  of  the 

leg. 
'     Communicating  (ramus  communicans), — to  join  a  similar  branch  of  the 

peroneal  artery. 
Internal  Calcanean  Branches  (rami  calcanei  mediales), — to  the  heel  and 

sole  of  the  foot. 
Internal  Malleolar  (a.  malleolaris  posterior  medialis). 

The  Internal  Plantar  Artery  (a.  plantaris  medialis),  the  smallest  of  the 
terminal  branches  of  the  posterior  tibial,  passes  along  the  inner  side  of  the 
foot  and  great  toe. 

The  External  Plantar  Artery  (a.  plantaris  lateralis)  sweeps  across  the 
plantar  aspect  of  the  foot  in  a  curve,  the  convexity  of  which  is  directed 
outward  and  forward;  and  at  the  interval  between  the  bases  of  the  ist 
and  2d  metatarsal  bones  it  inosculates  with  the  communicating  branch 


IMPORTANT    ARTERIAL   ANASTOMOSES  145 

frortl  the  dorsalis  pedis,  completing  the  Plantar  Arch   (arcus  plantaris") 
or  the  Stirrup  Anastomosis.     It  gives  off  numerous  muscular  branches, 
and  the — 
Posterior  Perforating  (rami  perforantes  posteriores), — 3  small  branches 

which  ascend  through  the  3  outer  interosseous  spaces  between  the 

heads  of  the  dorsal  interossei  muscles. 
Digital  Branches  (aa.  digitales  plantares),  4, — supplying  the  sides  of  the 

3  outer  toes  and  the  outer  side  of  the  2d  toe;  its  inner  side,  together 

with  the  great  toe,  being  supplied  by  the  communicating  branch  of 

the  dorsalis  pedis. 

ARTERIAL  ANASTOMOSES 

The  Anastomosis  around  the  Shoulder- joint  is  formed  by  the  following 
8  arteries,  viz.— 

Posterior  Scapular  (ramus  descendens  a.  trans  versa  colli). 
Subscapular  (a.  circumflexa  scapulae)  br.  of  axillary. 
Dorsalis  Scapula  (a.  circumflexa  scapulae)  br.  of  subscapular. 
Infraspinous,  br.  of  dorsalis  scapulae. 
S  upr  as  ca  pular  (a.  transversa  scapulae),  br.  of  thyroid  axis. 
Ant.  Circumflex  (a.  circumflexa  humeri  anterior),  br.  of  axillary. 
Post.  Circumflex  (a.  circumflexa  humeri  posterior),  br.  of  axillary. 
Acromial,  br.  of  acromial  thoracic. 

The  Anastomosis  around  the  Elbow-joint  is  formed  by  the — 

Superior  Profunda,  (a.  profunda  brachii),  br.  of  brachial. 

Posterior  Articular,  br.  of  superior  profunda. 

Radial  Recurrent,  br.  of  radial. 

Interosseous  Recurrent,  br.  of  posterior  interosseous. 

Inferior  Profunda  (a.  collateralis  ulnaris  superior),  br.  of  brachial. 

Anastomotica  Magna  (a.  collateralis  ulnaris  inferior),  br.  of  brachial. 

A  nterior  Ulnar  Recurrent,  br.  of  ulnar. 

Posterior  Ulnar  Recurrent,  br.  of  ulnar. 

The  Anastomotica  Magna  is  the  vessel  most  engaged  in  this  anastomosis, 
the  only  part  in  which  it  is  not  employed  being  that  in  front  of  the  ex- 
ternal condyle  of  the  humerus. 

The  Anastomosis  around  the  Hip-joint  is  formed  by  the — 
Gluteal  (superior  gluteal),  Ilio-lumbar,  and  Circumflex  Iliac,  with  the  Ex- 
ternal Circumflex. 

Obturator  and  Sciatic  (inferior  gluteal),  with  the  Internal  Circumflex. 
Comes  Nervi  Ischiadici,  with  the  Perforating  branches  of  the  Profunda. 
10 


146  HUMAN    ANATOMY 

The  Arteries  Anastomosing  around  the  Knee-joint  are  the — 

Descending,  br.  of  ext.  circumflex.  Sup.  Int.  Articular,  br.  of  popliteal. 
Anastomotica  Magna  (a.  genu  su-  Inf.  Ext.  Articular,  br.  of  popliteal. 

prema),  br.  of  femoral.  Inf.  Int.  Articular,  br.  of  popliteal. 

Inferior  Perforating,  br.  of  profunda.  Ant.  Recurent,  br.  of  anterior  tibial. 
Superior  Ext.  Articular,  br.  of  popliteal. 

This  anastomosis  is  sometimes  called  the  deep  plexus  of  the  Circum- 
patellar  Anastomosis;  a  superficial  arterial  plexus  being  situated  between 
the  fascia  and  skin  around  the  patella. 

.The  Crucial  Anastomosis  is  formed  behind  the  junction  of  the  neck  of 
the  femur  with  the  great  trochanter,  between  the  adductor  magnus  and 
quadratus  femoris  muscles,  by  the  anastomosis  of  the  following-named 
arteries: — 

Transverse  branch  of  Ext.  Circumflex  (from  profunda),  externally. 

Terminal  branch  of  Int.  Circumflex  (from  profunda),  internally. 

First  Perforating  branch  of  the  Profunda  Femoris,  below. 

Anastomotic  branch  of  the  Sciatic  (from. int.  iliac),  above. 

The  Longest  Anastomosis  in  the  Body  is  that  between  the  subclavian 
and  the  external  iliac  by  the  anastomosis  of  the  Superior  Epigastric,  br. 
of  the  internal  mammary,  with  the  Deep  Epigastric,  br.  of  the  external 
iliac. 

[The  circle  of  Willis  has  been  described  on  page  128;  the  palmar  and 
plantar  arches  on  pages  135  and  145  respectively;  and  the  anastomosis 
of  the  membrana  tympani  on  page  298.] 

The  Collateral  Circulation,  after  Ligature  of  the  Common  Carotid 
Artery,  is  established  by  the  free  communication  existing  between  the 
carotid  arteries  of  opposite  sides  both  within  and  without  the  cranium, 
and  by  enlargement  of  the  branches  of  the  subclavian  artery  on  the  ligated 
side.  Outside  the  skull  the  principal  communication  takes  place  by 
the  following  anastomoses: — 

Superior  Thyroid,  br.  of  the  external  carotid,  with  the  Inferior  Thyroid, 
br.  of  the  thyroid  axis  (from  the  subclavian). 

Arteria  Princeps  Cervicis,  br.  of  the  occipital  (from  the  external  carotid), 
with  the  Vertebral,  br.  of  the  subclavian,  and  the  Profunda  Cervicis, 
br.  of  the  superior  intercostal  (from  the  subclavian). 

After  Ligature  of  the  Subclavian  in  its  first  part,  the  Collateral  Circu- 
lation is  carried  on  by  the  following  anastomoses: — i,  that  between  the 
Superior  and  Inferior  Thyroid  arteries  (see  above);  2,  that  between  the  two 
Vertebrals;  3,  that  between  the  Internal  Mammary,  the  Deep  Epigastric 
and  the  Aortic  Intercostals;  4,  the  Superior  Intercostal  with  the  Aortic 


ARTERIAL    SYSTEM    TABULATED  147 

Intercoslals;  5,  the  Profunda  Cervicis  with  the  Princeps  Cervicis;  6,  the 
Scapular  branches  of  the  thyroid  axis  with  branches  of  the  Axillary;  7, 
the  Thoracic  branches  of  the  Axillary  with  the  Aortic  Intercostals. 


TABLES  AND  PLATES 


OF   THE 


ARTERIAL  SYSTEM 


NOTE. — The  arteries  in  the  following  plates  should  be  colored  red,  by  painting 
them  over  with  ordinary  crimson  ink,  or  water-color  paint,  using  a  fine  camel's- 
hair  brush  for  the  purpose. 

Figures  in  parentheses  in  these  tables  refer  to  the  number  of  another  table,  thus — 
Ext.  Carotid  (3)  means  Table  No.  3  of  the  External  Carotid  Artery. 


THE  ARTERIAL  SYSTEM 

i.  .1  Numerous  branches  through- 

Pulmonary  Artery.      ^  p^Zv' ART   Pat  3    f°Ut   "»   PU'm°nary 
(Plate  i.)  3)  J    carrying  venous  blood. 


HUMAN    ANATOMY 


THE  ARTERIAL  SYSTEM.— Continued 
R.  CORONARY  1 


2. 

Arch  of  Aorta. 
(Plate  i.) 


L.  CORONARY  J 


INNOMINATE 


to  the  muscular  tissue  of  the  heart. 


R.  COMMON  CAROTID 


R.  SUBCLAVIAN 
[  becomes  Axillary 


(8) 


Ext.  Carotid  (3). 
Int.  Carotid  (4). 
Vertebral  (5). 
Thyroid  Axis  (6). 
Int.  Mammary  (7). 
Sup.  Intercostal. 


L.  COMMON  CAROTID,  .    .  Same  as  R.  Common  Carotid. 
L.  SUBCLAVIAN,  .    .  Same  as  R.,  continuing  as  Axillary  (8). 


External  Carotid. 
(Plate  i.) 


Superior 

Thyroid. 


Lingual 


Submental 


Facial  or  Ex- 
ternal Max- 
illary. 


Muscular  and  Glandular  branches. 
Hyoid,  along  lower  border  of  os  hyoides. 
Superf.  Descending,  crosses  Com.  Carotid. 
Sup.  Laryngeal,  to  larynx  and  epiglottis. 
Crico-thyroid,  crosses  Crico-thyroid  membrane. 

(  Hyoid,  along  upper  border  of  bone. 

I  Dorsalis  Linguae,  to  tongue,  tonsil,  palate,  etc. 

I  Sublingual,  to  gland,  mouth,  gums. 

(  Ranine,  under  surface  of  tongue,  to  tip. 

Inf.  (Asc.)  Palatine,  to  soft  palate  and  tonsil. 
Tonsillar,  to  tonsil  and  root  of  tongue. 
Submandibular,  to  gland,  skin,  muscles. 

Superf.  Br.  anas.  inf.  labial. 

Deep  Br.  to  the  lip. 
Muscular,  to  pterygoid,  masseter,  buccinator. 
Inf.  Labial,  anas,  with  br.  of  ?th  and  sth  N. 
Inf.   Coronary  or  labial,  anas,   with  br.   of  inf. 

dental  art. 
Sup.  Coronary,    f  Art.  of  Septum  Nasi. 

or  labial.  \  Br.  to  ala  of  nose. 

Lateralis  Nasi,  to  ala  and  dorsum  of  nose. 
A  ngular,  termination  of  facial  trunk. 


Muscular,  to  digastric,  stylo-hyoid,  etc. 
Sterno-mastoid,  to  that  muscle. 
Auricular,  to  back  part  of  concha. 

Occipital •(  Inf.  Meningeal,  to  dura  mater  in  post,  fossa. 

Superf.    Br.    anas,    superf. 

cervical,  of  trans,  colli. 

Princeps  Cervicis  \  Deep  Br.  anas,  vertebral, 
and  deep  cerv.  br  of 
sup.  intercostal. 


ARTERIES  OF  THE  HEAD  AND  NECK. 


Plate 


'      i 

GOHTINUED 


Potter,  del.. 


T4Q 


150 


HUMAN   ANATOMY 


THE  ARTERIAL  SYSTEM.— Continued 


Post.  A  uricular. . 


Branches  (small),  to  muscles  and  glands. 
Stylo-mastoid,  to  tympanum,  mastoid  cells,  etc. 
Auricular,  to  cartilage  of  ear. 
Mastoid,  to  scalp  above  ear. 


j  Prevertebral,  brs.  to  muscles  and  nerves. 

Ascending  I  Tympanic,  to  inner  wall  of  tympanum. 

Pharyngeal.    ]  Meningeal  Branches,  to  dura  mater. 

[  Pharyngeal  Branches,  3  or  4  in  number. 


3- 

Superficial 

External 

Temporal. 

Carotid. 

(Contin- 

ued.) 

INTERNAL 

i. 

MAXILLARY. 

Divisions: 

i.  Maxillary. 

2.  Pterygoid. 

3.  Spheno- 

maxillary. 

Transverse  Facial,  lies  on  the  masseter. 
Anterior  Auricular  Branches,  to  pinna,  etc. 
Middle  Temporal,  supplies  that  muscle. 
Anterior  Temporal,  to  the  forehead. 
Posterior  Temporal,  along  side  of  head. 

_,  .  /  to  memb.  tympani,  anas,  with  Stylo- 

j.  ympanic\  . ,        ,.  __. -. 

(    mastoid  and  Vidian  arteries. 

Deep  Auricular,   to  outer  surface  of  the  mem- 
brana  tympani. 

Mid.  Meningeal,  to  dura  and  cranial  bones. 
Small  or  Accessory  Meningeal,  to  dura  and  Gas- 
serian  gang. 


Inferior  Dental     L*n*Ual'  to  m'm'  of  mouth" 
I  Mylo-hyoid,  in  that  groove. 

M^Tl   l  Tern"nal  Brs- 


Mandibular 


j  Deep  Temporal,  2,  under  temporal  muscle. 
I  Pterygoid  Brs.,  to  pterygoid  muscles. 
I  Masseteric  to  deep  surface  of  masseter. 
(  Buccal,  a  small  br.  to  buccinator. 


A  Iveolar 


Dental,  to  molars,  bicuspids. 
Branches,  to  antrum,  gums,  etc. 

(several  brs.  to  the  orbit. 
Ant.  Dental,  to  front  teeth,  an- 
trum. 

Post.  (Desc.)  Palatine,  to  palate,  glands,  etc. 
Vidian,  to  Eustachian  tube  and  pharynx. 
Ptery go- palatine,  to  Eustach.  tube  and  pharynx. 
Artery  of  Septum,  to  septum. 
External   Branches   3,    to   the 
nares,  antrum,  ethmoid  and 
sphenoid  cells. 


Spheno-  palatine 


ARTERIAL   SYSTEM   TABULATED 


THE  ARTERIAL  SYSTEM.— Continued 


Tympanic,  to  tympanum  by  foramen  in  carotid  canal. 

Arteria  Receptaculi  (several),  in  cavernous  sinus. 

Ant.  Meningeal,  to  dura  mater  of  ant.  fossa. 

r  Lacrimal,  to  that  gland,  lid,  etc. 

Supraorbital,  the  largest  sub-branch. 

.  ,  ,/  Meningeal,  to  dura. 
Post-Eihmotdal  \NasalBrs.,  to  nose. 

i.  • 

Ant.  Ethmoidal,  has  same  branches. 

Sup.  Palpebral,  arch  on  margin  of  lid. 

OPHTHALMIC. 

Inf.  Palpebral,  margin  of  lower  lid. 

Groups: 

Frontal,  to  muscles,  skin    1 

i.  Orbital. 

/  Transverse,            [Terminal  Branches. 

4. 

2.  Ocular. 

*    \DorsolisNasi.     J 

Internal 

(Plate  4. 

Carotid. 

Pig.  2.) 

Art.  Centralis  Retina,  to  the  retina. 

(Plate  i.) 

(  Ant.  Ciliary,  to  the  iris. 

Muscular   \  Superior,  to  ocular  muscles. 

2.   ' 

[  Inferior,  to  ocular  muscles. 

Short  Ciliary,  6  to  12,  around  optic  n. 

Long  Ciliary  2,  to  circles  on  iris. 

A  nlerior  Cerebral 


(  Ant.  Communicating,  2  lines  long. 
' '  \  Ganglionic  and  Frontal  branches. 


Middle  Cerebral 


/  Ganglionic,     Frontal,     Parietal,     and     Parieto- 


\    temporal  branches. 
Posterior  Communicating, 


anas,  with   Post.   Cerebral   of   Basilar,   to 

form  the  Circle  of  Willis. 
Anterior  Choroid,  to  the  choroid  plexus,  etc. 


BASILAR 


Post.  Cerebral     Post.  Commun. 


THE  CIRCLE  OF  WILLIS 

I^TERNAL 
CAROTID. 


Ant.  Cerebral 


ral  \ 


Post.  Cerebral     Post.  Commun. 


Ant'  Cerebral 


Ant. 
Commun. 


152 


HUMAN    ANATOMY 


THE  ARTERIAL  SYSTEM.— Continued 


s. 

VERTEBRAL 
(Plate  i.) 


Lateral  Spinal 


Anterior  Spinal 


Br.  to  spinal  cord  and  membranes. 
Br.  to  bodies  of  Vertebras  posteriorly. 
Muscular  Branches,  to  deep  cervical  muscles. 
Post.  Meningeal,  ramify  between  dura  mater  and  skull. 

joins  its  fellow  to  form  Ant.  Median  Artery  of  the 

spinal  cord. 
Posterior  Spinal,  to  spinal  cord  and  membranes,  laterally. 

/  Internal       \  to  cerebellum,  and  choroid  plexus 
Post.  Inf.  Cerebellar  s   _  ,       >        ,,        .v-ir^-i 

(  External      J      of  the  4th  Ventricle. 

Bulbar,  minute  branches  to  the  medulla  oblongata. 

/  to  Pons  Varolii,  etc. 
Transverse  s    T         .     ,.  ,  . 

(  Int.  Auditory,  to  that  canal. 

,   „      /to  the  cerebellum,  anas,  with  post. 
Ant.  Inf.  Cerebellar  \     .   ,  ...        f  ,,     .  ,      . 

(    inf.  cerebellar  of  Vertebral. 

Superior  Cerebellar,  to  pia  mater,  pineal  gland,  etc. 

Post.    Choroid,    to   choroid    plexus 
Ganglionic,  to  post,  lobes. 

Posterior  Cerebral •{  Ant.  Temporal, 

•n         m  I  terminal 

Post.  Temporal,         }•    , 

_     .    .    .  branches. 

Occipital, 


Inf.  Laryngeal,  to  post,  muscles  of  larynx. 
Tracheal  Brs.  to  trachea,  anas.  Bronchial. 
(Esophageal  Brs.  to  oesophagus. 
Ascending  Cervical,  to  muscles,  spinal  cord. 
Muscular,  to  muscles  of  hyoid  bone  and  of  the 

pharynx. 

Superficial  Cervical,  beneath  Trapezius. 
Posterior  Scapular,  along  post,  border. 
Supra-acromial,  anas.  Acromial  Thoracic. 
Supra-scapular.  .  .  .  I  Supra-sternal,  to  skin  of  the  chest. 
1  Muscular,  to  sterno-mastoid,  etc. 
I  Nutrient,  to  the  clavicle. 


6. 

THYROID 
Axis. 
(Plate  i.) 


Inferior  Thyroid. 


Transversalis   Colli. 


Comes  Nervi  Phrenici  (Superior  Phrenic),  to  Diaphragm. 
Mediastinal  Brs.  to  tissue  and  glands,  ant.  mediastinum. 
Pericardiac  Brs.  to  upper  part  of  pericardium. 
Sternal  Brs.  to  sternum  and  Triangularis  sterni. 
INTERNAL        Anterior  Intercostals,  to  5  or  6  upper  intercostal  spaces. 
MAMMARY.     Perforating,  to  Pectoralis  major,  mammary  gland,  etc. 
(Plate  i.)        •»*..„,..!„  ^i.^a^;^    /  Ant.  Intercostals,  to  lower  intercostal  spaces. 
Brs.  to  lower  pericardium,  Diaphragm,  etc. 
f  anas,  with  deep  Epigastric  of  Ext.  Iliac. 
\  supplies  abdominal  muscles  and  skin. 


Musculo-phrenic 
Superior  Epigastric 


ARTERIAL    SYSTEM    TABULATED 


Axillary. 

(Plate  2.) 
i  from  ist  part, 
i      "      2d     " 
3      "      3d     " 


THE  ARTERIAL  SYSTEM.— Continued 

j  Superior  Thoracic,  to  Pectoral  muscles  and  wall  of  thorax. 

(  Brs.  to  Pectorals  and  Deltoid. 
[  Acromio  Thoracic  -|  Descending,  to  both  these  muscles. 

[  Clavicular,  to  the  Subclavius. 

(  Alar  Thoracic,  to  glands  of  axilla. 

\  Long  Thoracic,  to  Serratus,  Pectorals  and  glands. 


Subscapular 


A  nterior  Circumflex 


[  Subscapular. 
Dorsalis  Scapulce  \  Infra-spinous. 

{  Median. 
Main  trunk  to  inf.  angle  of  the  scapula. 

f  around  neck  of  humerus,  to  Deltoid. 
1  Br.  to  shoulder-joint. 


Posterior  Circumflex 


\  around  neck  of  humerus,  to  Deltoid 
\    muscle  and  shoulder-joint. 

Becomes  BRACHIAL  (10),  at  lower  margin  of  tendon  of  the  Teres  major 
muscle. 

(Post.  Articular,  to  elbow-joint  anastomosis 
and  inner  side  of  arm. 
Main   trunk,   in  spiral   groove   of   the   hu, 
merus,  to  Deltoid,  Triceps,  etc. 

9.  Nutrient,  to  nutrient  canal  of  the  humerus. 

Brachial.        •    Inferior  Profunda  (sup.  uln.  collat.)  to  the  elbow-joint  anastomosis. 
(Plate   2.)  Anastomotica   Magna  (inf.  uln.  collat.),  transversely  inward  on 

Brachialis  anticus  muscles  to  the  elbow,  where  it  anastomoses 
with  several  arteries. 

Muscular,  3  or  4,  to  muscles  in  course  of  artery. 
Bifurcates  into  RADIAL  (10)  and  ULNAR  (n). 

(  Radial  Recurrent,  anas,  branches  of  Sup.  profunda. 
J  Muscular  Brs.  to  muscles  on  radial  side  of  arm. 

Ant.  Carpal,  to  wrist-joints,  anas.  Ant.  Carpal  of  Ulnar. 

Superficialis  Voice,  to  muscles  of  the  thumb. 


Post.  Carpal 


to  wrist-joints,  anas.  Post.  Carpal  of  Ulnar. 

Dorsal  Interosseous,  for  3d  and  4th  spaces. 
Metacarpal,  is  the  First  Dorsal  Interosseous  Branch. 
Dor  sales  Pollicis  2,  laterally  on  dorsum  of  thumb. 
Dorsalis  Indicts,  on  radial  side  of  index  dorsum. 


10. 
Radial. 

(Plate  2.)  2. 

1.  In  forearm. 

2.  In  wrist. 

3.  In  hand. 

Princeps  Pollicis,  2  Brs.  forming  arch  on  last  phalanx. 
Radialis  Indicts,  along  radial  side  of  index  ringer. 
Perforating  3  between  heads  of  last  Dorsal  Interossei. 

/  3  or  4  along  Interossei  muscles,  given 
Palmar  Interossea{       - .      „      %>  1 

\    off  by  Deep  Palmar  Arch. 

Palmar  Recurrent,  to  the  carpal  articulations. 

Forms  DEEP  PALMAR  ARCH  in  the  hand,  completed  by  inosculation  with 
the  Deep  Palmar  (Communicating)  from  the  Ulnar  Artery. 


154 


HUMAN   ANATOMY 


THE  ARTERIAL  SYSTEM.— Continued 


Anterior  Ulnar  Recurrent,  ascends  in  front  of  inner  condyle 
Posterior  Ulnar  Recurrent,  ascends  behind  inner  condyle. 

pierces  Interosseous  mem- 
brane, descending  to  back 
of  wrist. 

Anterior          •    Muscular  Branches. 
Interosseous     Nutrient,  of  both  bones. 

Br.  on  Pronator  quadratus. 
Interosseous  \  [  Median,  along  median  n. 


11. 
Ulnar. 

(Plate  2.) 

1.  In  forearm. 

2.  In  wrist. 

3.  In  hand. 


3. 


Posterior 
Interosseous 


to  back  of  wrist. 
Interosseous    Recurrent,    to 
elbow-joint   anastomosis. 
Muscular,  to  muscles  on  ulnar  side  of  arm. 


Anterior  Carpal,  to  joints,  anas.  Carpal  of  Radial. 

|  to  joints  of  wrist,  anas.  Carpal  of  Radial. 
Posterior  Carpal    j     forming  the  Post.  Carpal  Arch. 

[  Metacarpal,  to  little  finger. 

!anas.  with  termination  of  Radial 
Artery,  completing  the  Deep 
Palmar  Arch. 

from  convexity  of  Superf.  Palmar  Arch,  to  the 
sides  of  the  fingers,  except  the  radial  side  of 
the  index  finger  and  thumb  (supplied  from 
the  radial). 


Digital  4 


Forms  SUPERFICIAL  PALMAR  ARCH  in  palm  of  hand,  by  inosculating  with 
a  branch  from  the  Radialis  Indicis  of  the  Radial  Artery. 


Pericardiac  Branches,  distributed  to  the  pericardium. 
Bronchial  Arteries  3  nutrient  vessels  of  the  lungs. 

12.  (Esophageal,  4  or  5,  anas.  brs.  Inf.  Thyroid,  Phrenic,  Gastric. 

Thoracic        ^  Posterior  Mediastinal,  (several)  to  glands,  etc.,  in  mediastinum. 

Aorta.  I  Posterior  (Dorsal),  to  muscles  of  back. 

(Plate  3).  Intercostals.        I  Spinal,  to  the  spinal  cord  and  its  membranes. 

1 8.  |  Collateral  Intercostal,  along  upper  border  of  the 

1     next  rib  below. 


ARTERIES  OF  THE 
UPPER  EXTREMITY. 


\ 


Potter  del 


156 


HUMAN   ANATOMY 


THE  ARTERIAL  SYSTEM.— Continued 


l  Internal,  to  front  of  thorax  and  Diaphragm. 

Phrenic         |  External,  to  side  of  thorax. 

to  cardiac  orifice  of  stomach,  cardiac  end. 

-  rin  rfW  f            t 

then   along  lesser    curvature   to   pylorus, 

where  it  anas,  with  Pyloric  Br.  of  Hepatic 

Art. 

Pyloric,  to  pylorus,  anas.  Gastric  Art. 

f  Gastro-epiploica 

\     Dextra 

Gastro-duodenalis    <  D           *         , 
Pancreatico-duo- 

CcELIAC 

{    denalis  Superior. 

Axis. 

Hepatic    • 

TT               )  to  right  lobe. 
Right  Hepatic,   <   -, 
\  Cystic,  to  gall-bladder. 

Left  Hepatic,  to  left  lobe  of  liver. 

Pancreaticce  Parva  \ 

>  to  the  pancreas. 
Pancreatic  Magna    ) 

Splenic 

Gastric    Vasa   Brevia,    5   to  7,  to  the  greater 

or 

curvature  of  stomach. 

Lienal 

Gastro-epiploica   Sinistra,   along   the   greater 

curvature,  from  left  to  right. 

Terminal  Brs.  enter  hilum  of  Spleen. 

13- 

Inferior  Pancreatico-duodenal,  to  those  organs. 

Abdominal 

Vasa  Intestini  Tenuis  12  to  15,  form  arches  in  mesen- 

Aorta. 

tery,  in  several  series,  from  terminal  arches  branches 

(Plate  3.) 

ramify  on  intestines. 

Superior 
Mesenteric. 

/  Inferior,  anas.  Vasa  intes.  ten. 
Ileo-colic     <    0          .                   „  ..        ,      , 
^  Superior,  anas.  Colica  dextra. 

/  Desc.  Br.  \  Arches  branching  to  ascend- 
Cohca  Dextra  \    .        _        >  . 
1  Asc.  Br.    )    ing  colon. 

/  Right  \  Arches,     branching     to     trans- 
Colica  Media  <  _  *       >                 . 
\  Left      )    verse  colon. 

Supra-renal,  to  supra-renal  capsule. 

.    /  Brs.  to  substance  of  kidney. 
Renal    \ 

{  Small  Brs.  to  capsule,  ureter,  etc. 

Spermatic  (or  Ovarian)  to  testes  or  ovaries,  uterus,  etc. 

Inferior 

(Asc.     \  Arches  branching  to  descend- 
Colica  Sinistra  <    ^          V 
[  Desc.    J      ing  colon. 

Mesenteric. 

Sigmoid,  across  Psoas  to  that  flexure  of  colon. 

(Plate  A  } 

(    KY    tn  ricrlit  1 

^i  late  4v 

Sup.  Hemorrhoidal,  <        '         ^       >  side  of  rectum. 

to  muscles,  etc.,  of  back. 
Spinal,  to  canal  s    „  '  \  Arches. 


Abdominal,  between  abdominal  muscles. 
Middle  Sacral,  to  coccyx,  anas.  Lateral  Sacral. 

/  RIGHT  COM.  ILIAC,  R.  Int.  and  Ext.  Iliac  (14,  15). 

Bifu.rc3.t6S    s 

Bifurcation  occurs  at  4th  Lumbar  Vertebra,  opposite  Umbilicus. 


BRANCHES  OF  THE  AORTA 


Plate  3. 


Potter.del 


157 


HUMAN   ANATOMY 


THE  ARTERIAL  SYSTEM.— Continued 


Superior  Vesical 


Obturator. 


\  Art.  of  Vas  Defer  ens,  to  that  organ. 
\  Middle  Vesical,  to  base  of  bladder. 


14  a. 
Internal  Iliac  or 

Uterine,            < 

Hypogastric.     , 

I 

ANTERIOR 

Vaginal,  analog 

TRUNK. 

(Plate  4.) 

Internal 

Pudic,  or 

Pudendal. 

Sciatic  or 

Inf.  Gluteal. 

Iliac,  to  iliac  bone  and  Iliacus  muscle. 

Vesical,  backward  to  the  bladder. 

Pubic,  on  the  back  of  the  pubic  bone. 

Internal,  along  inner  margin  obturator  foramen. 

External     /  outer  margm  obturator  foramen. 

\  Br.  to  hip-joint  by  cotyloid  notch. 
Inferior  Vesical,  to  base  of  bladder,  prostate  gland,  etc. 
Middle  Hemorrhoidal,  to  anus,  anas,  other  hem.  arteries, 
f  Br.  to  the  bladder.  ] 

Br.  to  the  ureter. 

Cervical,  to  neck  of  uterus. 

Azygos,  of  the  vagina. 


In  the  female. 


Inferior  Hemorrhoidal,  2  or  3  to  the  anus. 
Superficial  Perinaal,  to  the  scrotum,  etc. 
Transverse  Perinceal,  to  muscle  of  same  name. 
Artery  of  the  Bulb,  large  but  very  short. 
Artery  of  the  Corpus  Cavernosum,  to  that  body. 
Dorsal  Artery  of  the  Penis,  or  clitoris. 

Muscular  Brs.  within  the  pelvis. 
Hemorrhoidal  Brs.  to  the  rectum. 
Vesical  Brs.  to  base  and  neck  of  bladder. 
Coccygeal,  to  back  of  coccyx. 
Inf.  Gluteal  3  or  4,  to  Gluteus  maximus. 
Comes  Nervi  Ischiadici,  along  sciatic  nerve. 
Muscular  Brs.  to  back  of  hip. 
Anastomotic,  to  the  crucial  anastomosis. 
Articular  Brs.  to  capsule  of  the  hip- joint. 


ARTERIES  or  THE  PELVIS  AND  THIGH.  Plate  4 


FIG.  2 

BRANCHES  Ot  OPHTHALMIC  ARTtRY. 


Potter  .del 


159 


i6o 


HUMAN   ANATOMY 


THE  ARTERIAL  SYSTEM.— Continued 


14  b. 

Internal  Iliac  or 

Hypogastric. 

POSTERIOR 

TRUNK. 

(Plate  4.) 


Ilio-lumbar, 


Iliac,  to  Iliacus  internus  and  Ilium. 

/  to  Psoas  and  Quad,  lumborum. 


Lumbar, 


\  Spinal  Br.  to  cord  and  membranes. 


Superior  Lateral  Sacral,  to  dorsum  of  sacrum. 
Inferior  Lateral  Sacral,  to  front  of  sacrum,  and  coccyx,  anas 
with  Sacra  media,  etc. 


Gluteal, 


Muscular  Brs.  within  the  pelvis. 

Nutrient,  of  the  Ilium. 

Superficial,  to  Gluteus  maximus,  etc. 

Superior,  to  ant.  sup.  spine  of  Ilium. 

Inferior,  to  glutei  and  hip-joint. 


Deep 


Muscular  Brs.  several,  to  Psoas  and  glands. 

15.  [  Cremasteric,  to  cremaster  muscle. 

External     Iliac.  •    Epigastric,   -I  Pubic,  to  inner  side  of  femoral  ring. 

(Plate  4.)  (  Muscular,  to  abdominal  muscles  and  skin. 

„.          ,,      rf.        \  between  Transversalis  and  Int.  oblique. 
Circumflex  Iliac,  <    _  .  .    T        ,  ,  _    .          . 

(  Br.  anas,  with  Lumbar  and  Epigastric. 

Becomes  FEMORAL  (16)  at  Poupart's  Ligament. 


Superficial  Epigastric,  in  superf.  fascia,  to  umbilicus. 

Superf.  Circumflex  Iliac,  outward  to  iliac  crest. 

Superf.  Ext.  Pudic  (pudendal) ,  inward  to  skin  of  penis,  scrotum 

etc. 
Deep  Ext.  Pudic  (pudendal),  inward  to  skin  of  perineum,  etc. 


Asc.  Brs.  outer  side  of  hip. 
Ext.  Circumflex,  •{  Transverse,  to  back  of  hip. 
Descending,  as  far  as  knee. 


16. 
Femoral. 

(Plate  4.) 


Profunda 
Femoris, 


I  Ascending,  to  Adductors,  etc. 
Int.  Circumflex,  -j  Descending,  to  Adductors,  etc. 

[  Articular,  to  head  of  femur, 
f  Superior,  pierces  Adductor  magnus. 


Perforating,^,  Middle,  <  Nutrient  of  Femur. 

{  Inferior,  pierces  Adductor  magnus. 

Muscular  2  to  7,  along  artery,  to  Sartorius,  Vastus  internus,  etc. 

j  Superficial  Br.  to  integument. 

Anastomotica  Magna,}  Deep  Br.  to  inner  side  of  knee  and  joint, 
or  Genu  Suprema.  anas,  with  Sup.  Articulars  and  Recur- 

[      rent  br.  of  Anterior  Tibial. 
Becomes  POPLITEAL  (17),  at  opening  in  Adductor  magnus. 


ARTERIES  OF  THE  LEG.  | 


Plate  5 


Potter.dei 


II 


161 


HUMAN    ANATOMY 


THE  ARTERIAL  SYSTEM.— Continued 


17- 
Popliteal. 

(Plate  4.) 


Muscular 


/  Superior  Brs.  to  Vastus  ext.  and  flexor  muscles. 


\  Inferior  or  Sural  2,  to  Gastrocnemius  and  Plantaris. 
Cutaneous  Brs.  to  integument  of  calf. 
Superior  Internal  Articular,  to  Vastus  int.  and  joint. 
Superior  External  Articular,  to  Vastus  ext.  and  joint. 
Azygos  Articular,  to  synovial  membrane  of  joint. 
Inferior  Internal  Articular,  to  head  of  tibia  and  joint. 
Inferior  External  Articular,  to  front  of  knee-joint. 


.    ,     /  ANTERIOR  TIBIAL  (i 8)    \at    lower    border    of    Popliteus 
Bifurcates  into  |  pOSTERIOR  TlBIAL  (lp)  |      musde 


Post.  Recurrent  Tibial,  to  the  Popliteus  muscle. 
Superior  Fibular,  to  the  Soleus  and  Peroneus  longus. 
Ant.  Recurrent  Tibial,  to  the  knee-joint  anastomosis. 
18.  Muscular  Brs.  numerous  to  muscles  of  leg. 

Anterior  I  Internal  Malleolar,  beneath  tendon  of  Tibialis  anticus. 

Tibial.  j  External  Malleolar,  to  outer  ankle. 

(Plate  5.)  Tar  sal,  to  tarsal  joints  and  Ext.  brev.  digit. 

7  Digital 
branches. 


Dorsalis    Pedis 


Metatarsal,  <  3  Interossea, 


Dorsalis  Hallucis 


Communicating, 


Ends  in  the  PLANTAR  ARCH. 


Brs.  to  great  toe. 
Br.  to  inner  side  of  2d  toe. 
anas.  Ext.  Plantar  (Arch). 
2  Digital  Brs. 


Peroneal, 


Anterior  Peroneal,  pierces  interosseous  membrane. 
Posterior  Peroneal,  to  the  os  calcis. 
Nutrient* Artery  of  the  fibula. 
Muscular,  several  brs.  in  its  course. 

/  joins  similar  branch  of  the  poste- 
Commumcating   { 

\      nor  Tibial. 

Ext.  Calcanean,  the  terminal  branches. 
19.  Muscular,  to  Soleus,  etc.,  on  back  of  leg. 

Posterior  I  Nutrient  of  Tibia,  the  largest  nutrient  artery  of  bone. 

Tibial.     Communicating  Br.  to  a  similar  br.  of  the  Peroneal. 
(Plate  5.)  Internal  Calcanean  Brs.  to  the  heel,  and  sole  of  foot. 

Internal  Plantar,  along  inner  side  of  foot  and  great  toe. 
(  Brs.  to  muscles,  fascia  and  skin. 
Posterior  Perforating  3  Branches. 

4  Digital,  {  Ant.  Perforating  Branches. 
k  I 

Ends  as  the  PLANTAR  ARCH,  anas,  with  Commun.  Br.  of  Dorsalis  Pedis. 


External  Plantar, 


THE   VEINS  163 

THE  VEINS 

Veins  are  vessels  which  return  the  blood  from  the  capillaries  of  the  body 
to  the  heart.  Their  walls,  like  those  of  the  arteries,  are  composed  of  3 
coats — an  internal  serous  (tunica  intima),  a  middle  muscular  (tunica 
media),  and  an  external  one  (tunica  externa  or  adventitia)  of  connective 
tissue.  Their  middle  coat  is  weaker  than  that  of  the  arteries,  so  that  they 
do  not  stand  open  when  divided,  as  the  arteries  do.  They  all  carry  carbon- 
ized (venous)  blood,  except  the  pulmonary  veins,  which  bring  oxygenated 
blood  to  the  left  side  of  the  heart.  The  deep  veins  accompany  the  arteries, 
generally  in  the  same  sheath,  and  are  given  the  same  names.  The  second- 
ary arteries,  as  the  radial,  ulnar,  brachial,  etc.,  have  each  two  veins,  called 
Vena  Comites.  The  superficial  veins  are  usually  unaccompanied  by 
arteries,  and  lie,  as  a  rule,  between  the  layers  of  the  superficial  fascia, 
terminating  in  the  deep  veins.  Many  veins  are  so  irregular  in  their 
origin  that  they  cannot  be  accurately  described;  they  all  anastomose  with 
each  other  much  more  freely  than  do  the  arteries. 

Venous  Sinuses  are  venous  channels,  differing  from  veins  in  structure, 
but  answering  the  same  purpose.  Those  of  the  cranium  are  formed  by 
the  separation  of  the  layers  of  the  dura  mater. 

The  Veins  are  divided  into  the  Pulmonary,  Systemic,  and  Portal  Sys- 
tems; the  latter  being  an  appendage  of  the  systemic,  its  capillaries  ramify- 
ing in  the  liver. 

Veins  having  no  valves  are  the  venae  cavae,  hepatic,  portal,  renal, 
uterine,  ovarian,  cerebral,  spinal,  pulmonary,  umbilical,  and  the  very  small 
veins. 

The  Pulmonary  Veins  alone  of  the  veins  carry  arterial  blood,  beginning 
in  the  capillaries  of  the  lungs,  forming  a  single  trunk  for  each  lobule,  which, 
uniting  into  a  single  trunk  for  each  lobe,  form  two  main  trunks  from  each 
lung  which  open  separately  into  the  left  auricle.  Sometimes  the  three  lobe- 
trunks  of  the  right  lung  remain  separate  to  their  termination  in  the  auricle, 
and  not  infrequently  a  common  opening  serves  for  the  two  left  pulmonary 
veins. 

VEINS  OF  THE  HEAD  AND  NECK 

Exterior  Veins  of  the  Head  and  Face  are  as  follows, — 
Frontal  Vein, — begins  on  the  anterior  part  of  the  skull  by  a  venous  plexus 

converging  to  a  single  trunk  near  the  middle  line  of  the  forehead,  which 

joins  the  supra-orbital  vein  at  the  root  of  the  nose  to  form  the  angular 

vein. 
Supra-orbital  Vein, — begins  on  the  forehead  and  joins  the  frontal  (see 

above)  to  form  the  angular  vein. 


1 64  HUMAN    ANATOMY 

Angular  Vein, — formed  as  described  above,  runs  downward  and  outward 
on  the  side  of  the  root  of  the  nose,  communicates  with  the  ophthalmic 
vein,  and  ends  in  the — 

Facial  Vein, — a  direct  continuation  of  the  angular,  begins  at  the  side  of  the 
root  of  the  nose,  descends  obliquely  across  the  masseter  muscle  and 
over  the  body  of  the  lower  jaw  to  unite  with  the  ant.  division  of  the 
temporo-maxillary  to  form  the  common  facial  vein,  which  enters  the 
internal  jugular. 

Temporal  Vein, — begins  on  the  vertex  and  side  of  the  skull,  by  anterior  and 
posterior  branches  which  unite  and  are  joined  by  the  middle  temporal 
above  the  zygoma  to  form  the  trunk,  which  descends  through  the  parotid 
gland  and  unites  with  the  internal  maxillary  to  form  the  temporo- 
maxillary  vein. 

Internal  Maxillary  Vein, — is  formed  by  branches  corresponding  to  those  of 
the  internal  maxillary  artery,  forming  the  pterygoid  plexus.  The  trunk 
passes  backward  behind  the  neck  of  the  lower  jaw  and  unites  with  the 
temporal  to  form  the — 

Temporo-maxillary  Vein, — descends  in  the  parotid  gland  and  divides  into 
an  anterior  branch,  which  joins  the  facial,  and  a  posterior  branch  which 
is  joined  by  the  posterior  auricular  and  becomes  the  external  jugular. 

Posterior  Auricular  Vein, — begins  on  the  side  of  the  head,  descends  behind 
the  external  ear  and  joins  the  posterior  division  of  the  temporo-maxillary, 
forming  the  external  jugular. 

Occipital  Veins, — begin  in  a  plexus  at  the  back  of  the  head  and  terminate 
in  the  internal  jugular. 

Veins  of  the  Diploe  and  Interior  of  the  Cranium, — 

-  Veins  of  the  Diploe, — a  number  of  tortuous  canals  lying  between  the  two 
tables  of  the  skull,  and  divided  into  frontal  (empties  into  supra-orbital), 
anterior  temporal  (empties  into  either  the  spheno-parietal  sinus  or  ante- 
rior deep  temporal),  posterior  temporal  and  occipital  branches  which 
empty  into  either  the  occipital  vein  or  the  lateral  sinus  (sinus 
transversus)  .^ 

Cerebral  Veins, — have  no  muscular  coat  and  no  valves.  They  are  divided 
into  superficial  and  deep  sets.  The  deep  cerebral  are  formed  by  the 
union  of  the  vena  cor  ports  striati  (vena  terminalis)  and  the  choroid  vein 
on  either  side,  and  receive  the  basilar  vein,  forming  the  great  cerebral 
vein  (veins  of  Galen). 

Ccrcbcllar  Veins, — on  the  surface  of  the  cerebellum,  are  disposed  in  3  sets, 
superior,  inferior  and  lateral. 

Superior  Longitudinal   Sinus    (sinus   longitudinalis  vel    sinus  sagittalis 


DURAL    SINUSES  165 

superior), — occupies  the  attached  margin  of  the  falx  cerebri,  begins  at 

the  foramen   caecum,   and  ends  in  the  torcular  Herophili   (confluens 

sinuum),  or  confluence  of  the  sinuses. 
Inferior.  Longitudinal  Sinus  (sinus  sagittalis  inferior), — in  the  free  margin 

of  the  falx  cerebri  posteriorly,  terminates  in  the — 
Straight  Sinus  (sinus  rectus  or  tentorial  sinus), — at  the  junction  of  the  falx 

cerebri  with  the  tentorium,  terminates  in  the  lateral  sinus  (sinus  trans- 

versus)  of  the  opposite  side. 

Lateral  Sinuses  (sinus  transversi), — in  the  attached  margin  of  the  ten- 
torium cerebelli,  terminate  in  the  internal  jugular  vein. 
,~"    Occipital  Sinuses  (sinus  occipital es), — in  the  attached  margin  of  the  falx 

cerebri,  terminate  in  the  torcular  Herophili. 
Cavernous  Sinuses  (sinus  cavernosi), — one  on  each  side  of  the  sella  turcica, 

receive  the  ophthalmic  vein  and  open  behind  into  the  petrosal  sinuses. 
Circular  Sinus  (sinus  circularis), — is  formed  by  two  transverse  vessels,  the 

anterior    and    posterior    intercavernous    sinuses,    connecting    the    two 

cavernous  sinuses,  and  forming  a  venous  circle  around  the  pituitary 

body. 
Superior  Petrosal  Sinus, — connects  together  the  cavernous  and  lateral 

sinuses  of  each  side. 
Inferior  Petrosal  Sinus, — begins  at  the  termination  of  the  cavernous  sinus, 

and  joins  the  lateral  sinus  to  form  the  internal  jugular  vein. 
Transverse  or  Basilar  Sinus  (plexus  basilaris], — connects  the  two  inferior 

petrosal  sinuses  over  the  basilar  process  of  the  occipital  bone. 
Emissary  Veins  (emissaria), — pass  through  apertures  in  the  cranial  wall 

from  the  sinuses  inside  to  the  veins  outside;  the  principal  ones  being  8 

in  number. 

1.  Frontal  through  foramen  caecum. 

2.  Parietal  (two)  through  parietal  foramina. 

.3.  Occipital  through  foramen  in  occipital  protuberance  (occasional). 

4.  Post-condylar  (condyloid)  through  foramen  behind  occipital  condyle. 

5.  Emissary  plexus  through  foramen  ovale. 

6.  Vein  of  Vesalius  through  foramen  of  Vesalius. 

7.  Plexus  through  internal  carotid  canal. 

8.  Plexus  through  anterior  condylar  canal  (hypoglossal  canal). 

Veins  of  the  Neck,  draining  those  above-mentioned,  are  the — 
External  Jugular  (6), — terminating  in  the  subclavian  vein  (4). 
Posterior  External  Jugular, — opens  into  the  external  jugular. 
Anterior  Jugular  (7), — enters  the  subclavian  vein  near  the  external  jugular. 
Internal  Jugular  (5), — formed  by  the  junction  of  the  two  last-named 


i66 


HUMAN    ANATOMY 


sinuses  at  the  jugular  foramen,  and  uniting  with  the  subclavian  vein  to 
form  the  innominate,  at  the  root  of  the  neck.  In  its  course  it  receives 
the  facial,  lingual,  pharyngeal,  superior  and  middle  thyroid  veins,  and 
the  occipital. 

Vertebral, — descends  the  foramina  in  the  transverse  processes  of  the  cervical 
vertebrae,  and  empties  into  the  innominate  vein.  In  its  course  it 
receives  the  anterior  and  posterior  vertebral  and  many  other  veins. 

VEINS  OF  THE  UPPER  EXTREMITY 

Veins  of  the  Hand,  Forearm,  and  Arm  are  in  two  sets,  superficial  and 
deep.  The  superficial  set  lies  in  the  superficial  fascia,  begin  in  the  hand 
by  external  and  internal  dorsal  and  superficial  galmar  veins,  and  are 
continued  as  follows,  the  basilic  continuing  as  the  axillary,  which  receives 
the  cephalic  just  below  the  clavicle. 

Radial  (cephalic  B.N.A.)  ./i^.^  \  f 

. .    >  Cephalic 

Median  Cephalic  } 

Profunda 
Median  Basilic 


Dorsal. 


Palmar. 


Dorsal. 


Median  (median 
cubital) 

I  Anat.  Ulnar 
!     (basilic  B.N.A. 
|  Post.  Ulnar 
{     (basilic  B.N.A. 


Common  Ulnar 
(basilic  B.N.A.) 


Basilic 


AXIL- 
LARY 
VEIN. 


The  deep  veins  follow  the  arteries,  generally  as  venae  comites,  beginning 
in  the  hand  as  Digital,  Interosseous  and  Palmar  veins,  they  unite  in  the 
Deep  Radial  and  Deep  Ulnar,  which  join  to  form  the  Vena  Comites  of 
the  brachial  artery  at  the  bend  of  the  elbow.  The  Brachial  Veins  lie 
one  on  each  side  of  the  brachial  artery  and  join  the  Axillary  Vein.  These 
deep  veins  have  numerous  anastomoses,  not  only  with  each  other  but  also 
with  the  superficial  ones. 

Axillary  Vein  (v.  axillaris), — the  continuation  of  the  basilic,  lies  on 
the  inside  of  the  artery  and  terminates  beneath  the  clavicle  at  the 
outer  border  of  the  ist  rib,  where  it  becomes  the — 
Subclavian  Vein  (v.  subclavia), — the  continuation  of  the  axillary, 
extends  from  the  outer  border  of  the  ist  rib  to  the  inner  end  of  the 
clavicle,  where  it  unites  with  the  internal  jugular  to  form  the  in- 
nominate vein.  At  the  angle  of  junction  enters  the  thoracic  duct  on 
the  left  side  of  the  body  and  the  right  lymphatic  duct  on  the  right 
side.  In  its  course  it  receives  the  external  and  anterior  jugular 
veins  and  a  branch  from  the  cephalic. 
The  Innominate  Vein  (vena  anonyma)  is  formed  by  the  union  of  the 


VEINS    OF    THE    THORAX 


i67 


subclavian  and  the  internal  jugular.     The  two  innominates  unite  just 
below  the   ist  costal  cartilage  to  form  the  superior  vena  cava.     The 
Right   Innominate  (v.  anonyma   dextra)   (3)  is 
about   i    inch   long,   and   receives,   besides   its  FIG.  69. 

constituent  branches,  the  right  internal  mam- 
mary, right  inferior  thyroid,  and  right  superior 
intercostal  veins.  The  Left  Innominate  (v. 
anonyma  sinistra)  (2)  is  about  2^  inches  long; 
in  its  course  it  receives  the  vertebral,  inferior 
thyroid,  internal  mammary,  and  superior  inter- 
costal veins  of  the  left  side. 

VKIXS  OF  THE  THORAX 

The  Veins  of  the  Thorax  include  the  follow- 
ing vessels: — 
,*    Internal  Mammary,  (mamariainterna), — two  to 

each  artery,  unite  into  a  single  trunk  which 

terminates  in  the  innominate  vein. 
Inferior  Thyroid   (vv.  thyreoideae  inferiores), — 

2  to  4,  form  a  plexus  in  front  of  the  trachea, 

which  gives  off  the  left   and  right   inferior 

thyroid    veins,    these  receiving    cesophageal, 

tracheal   and    inferior    laryngeal    veins    and 

opening  into  the  innominate  veins. 
Superior  Intercostal, — the  right  vein  (v.  inter- 

costalis  suprema  dextra)  opens  into  the  vena 

azygos  major,  the  left  vein  (v.  intercostalis 

suprema  sinistra)  into  the  left  innominate. 
Azygos  Veins, — are  described  below. 
*  Bronchial, — return    the    blood    from    the  lung 

substance;  the  right  one  opens  into  the  vena 

azygos  major,  the  left  into  the  left  superior 

intercostal  or  the  left  upper  azygos  vein. 
Spinal, — are  described  below. 
Vena  Cavce^ — are  described  below;  the  Superior  Vena  Cava  under  the 

Veins  of  the  Thorax,  the  Inferior  Vena  Cava  under  the  Veins  of  the 

Lower  Extremity. 

The  Azygos  Veins  supply  the  place  of  the  venae  cavae  in  the  region 
where  these  trunks  are  deficient,  being  connected  with  the  heart. 

Vena  Azygos  Major  (v.  azygos)  (17), — begins  by  a  branch  from  the  right 
lumbar  veins  usually,   passes  through  the  aortic  opening  in   the 


l68  HUMAN    ANATOMY 

diaphragm,  and  ends  in  the  superior  vena  cava,  having  drained  10 
right  lower  intercostals,   the  vena  azygos  minor,  (v.  hemiazygos), 
the  right  bronchial,  cesophageal,  mediastinal,  and  pericardial  veins. 
Left  Lower  Azygos  (vena  azygos  minor  or  v.  hemiaz3'gos)  (18), — begins 
by  a  branch  from  the  left  lumbar  or  renal,  passes  through  the  left 
crus  of  the  diaphragm,  crosses  the  vertebral  column  and  ends  in  the 
right  azygos,  having  drained  4  or  5  lower  intercostals. 
Left   Upper  Azygas   (v.  hemiazygos  accessoria), — drains  3   or  4  left 
intercostals  and  empties  into  either  of  the  other  two.     It  is  often 
wanting,  its  place  being  filled  by  the  left  superioi  intercostal  vein  (21). 
The  Spinal  Veins  may  be  arranged  in  4  sets,  as  follows: — 
Qor  si- spinal, — form  a  plexus  around  the  spines,  processes,  and  laminae 
of  all  the  vertebrae.     They  empty  into  the  vertebral,  intercostal,  lumbar, 
and  sacral  veins  in  their  respective  regions. 

Meningo-rachidian, — in  two  longitudinal  plexuses,  anterior  and  posterior, 
running  the  whole  length  of  the  spinal  canal.  The  posterior  join  the 
dorsi-spinal  veins,  the  anterior  empty  into  the  vertebral,  intercostal, 
lumbar,  and  sacral  veins  in  their  various  regions. 

Vena  Basis  Vertebrarum—the  veins  of  the  bodies  of  the  vertebrae,  are 
contained  in  large,  tortuous  channels  in  the  substance  of  the  bones,  and 
join  the  transverse  trunk  connecting  the  anterior  longitudinal  veins. 
Medulli-spinale, — the  veins  of  the  spinal  cord,  lie  in  plexus  form  between 
the  pia  mater  and  arachnoid.  They  unite  into  2  or  3  small  trunks  near 
the  base  of  the  skull,  which  terminate  in  the  inferior  cerebellar  veins 
or  in  the  inferior  petrosal  sinuses. 

The  Superior  Vena  Cava  (i)  is  a  short  trunk  about  2^  or  3  inches  in 
length,  formed  by  the  union  of  the  two  innominate  veins,  thereby  re- 
ceiving all  the  blood  from  the  upper  half  of  the  body,  and  opening  into  the 
right  auricle  of  the  heart.  It  is  half  covered  by  the  pericardium,  and 
receives  the  vena  azygos  major  and  small  pericardiac  and  mediastinal 
veins. 

VEINS  OF  THE  LOWER  EXTREMITY 

The  Veins  of  the  Lower  Extremity  are  in  two  sets,  superficial  and  deep. 
The  superficial  are  the — 

Internal  or  Long  Saphenous  (saphena  magna), — on  the  inside  of  the 
leg  and  thigh,  enters  the  femoral  at  the  saphenous  opening  i  >£  inch 
below  Poupart's  ligament  (1.  inguinale).     In  its  course  it  receives: — 
Cutaneous  Branches.  Superficial  Circumflex  Iliac. 

Superficial  Epigastric.  Communicating   Branches. 

Ext.  Pubic,  (venae  pudendae  externae). 


VEINS    OF   THE   PELVIS   AND   ABDOMEN  1 69 

External  or  Short  Saphenous  (v.  saphena  parva), — formed  by  branches 

from  the  dorsum  and  outer  side  of  the  foot,  it  ascends  behind  the 

outer  malleolus,  up  the  middle  of  the  back  of  the  leg,  and  empties  into 

the  popliteal  vein,  between  the  heads  of  the  gastrocnemius  muscle. 

The  deep  veins  are  the  vence  comites  of  the  arteries,  beginning  in  the  foot 

as  the  external  (lateral)  and  internal  (medial)  Plantar,  which  unite  to  form 

the  Posterior   Tibial    (venas  tibiales    posteriores).     The  vena  comites  of 

the  dorsalis  pedis  artery  continue  upward  as  the  Anterior  Tibial  veins 

(venae  tibiales  anteriores),  which  join  the  posterior  tibial,  forming  the — 

Popliteal, — which  becomes  the  Femoral,  and  it  the  External  Iliac,  in 

the  same  manner  as  the  respectively  named  arteries. 

VEINS  OF  THE  PELVIS  AND  ABDOMEN 

The  Veins  of  the  Pelvis,  except  the  middle  sacral,  open  into  the  internal 
iliac  vein.  The  middle  sacral  opens  into  the  left  common  iliac. 

The  Internal  Hiac  Vein  (vena  hypogastrica)   (10)  is  formed  by  the 
venae  comites  of  the  branches  of  the  internal  iliac  artery,  and  terminates 
with  the  external  iliac,  at  the  sacro-iliac  articulation,  to  form  the  common 
iliac  vein  (v.  iliaca  communis).     It  receives  the  following  veins: — 
From  the  exterior  of  the  pelvis,  the — 
Gluteal,  (v.  glutaea  superior). 
Sciatic  (v.  glutaea  inferior). 
Internal  Pudic  (vv.  pudendae  internae). 
Obturator. 
From  the  organs  in  the  pelvic  cavity  the — 

Hemorrhoidal  Plexus.     \  .  Uterine  Plexus.  \  . 

,,    .  ,  J .    „,  >  in  the  male.  ,,.,„,  >  in  the  female. 

Vesico- pro  static  Plexus.  J  Vaginal  Plexus.  J 

The  Dorsal  Vein  of  the  Penis  enters  the  prostatic  plexus. 

The  Veins  of  the  Abdomen  include  the  Portal  System,  the  Lumbar, 
Spermatic,  Renal,  Suprarenal,  Phrenic,  Hepatic,  External  Iliac,  Common 
Iliac  and  the  Inferior  Vena  Cava. 

The  External  Iliac  Vein  commences  at  the  termination  of  the  femoral 
beneath  Poupart's  ligament,  and  terminates  opposite  the  sacro-iliac  syn- 
chondrosis  by  uniting  with  the  internal  iliac  to  form  the  common  iliac 
vein.  It  receives  the  Deep  Epigastric  (v.  epigastrica  inferior)  and  Deep 
Circumflex  Iliac,  also  a  small  pudic  vein. 

The  Common  Iliac  Veins  (n)  are  each  formed  by  the  union  of  the  two 
iliac  veins  as  above  described,  and  unite  between  the  4th  and  5th  lumbar 
vertebras  to  form  the  inferior  vena  cava,  the  right  common  iliac  being  the 
shortest  of  the  two,  Each  receives  the  Ilio-lumbar,  sometimes  the  Lateral 


1 70  HUMAN    ANATOMY 

Sacral,  and  the  left  one  in  addition  the  Middle  Sacral  Vein,  which  some- 
times ends  in  the  vena  cava. 

The  Inferior  Vena  Cava  (8)  extends  from  the  junction  of  the  two 
common  iliac  veins,  passing  along  the  front  of  the  spine,  through  the  tendin- 
ous centre  of  the  diaphragm,  to  its  termination  in  the  right  auricle  of  the 
heart.  It  receives  the  following  veins: 

/      Lumbar  (12), — 4  on  each  side,  receive  dorsal  and  abdominal  tributaries, 
also  veins  from  the  spinal  plexuses,  and  terminate  in  the  inferior  vena 
cava.     They  are  connected  together  by  the  ascending  lumbar,  which 
passes  in  front  of  the  transverse  processes  of  the  lumbar  vertebrae. 
;,,     Right  Spermatic  (13). — The  spermatic  veins  arise  from  the  testis  and 
epididymis,  forming  the  spermatic  or  pampiniform  plexus,  which  forms 
the  chief  mass  of  the  spermatic  cord,  and  unite  into  3  or  4  veins  which 
enter  the  abdomen  through  the  internal  ring,  form  2  veins,  then  a 
single  one  which  opens  on  the  right  side  into  the  inferior  vena  cava,  on 
the  left  side  into  the  left  renal  vein.     In  the  female  they  are  called 
Ovarian  and  terminate  in  the  same  way  as  in  the  male. 
^   Renal  (15), — are  large  veins,  placed  in  front  of  the  renal  arteries,  and 
terminating  in  the  inferior  vena  cava.     The  left  is  longer  than  the 
f       right  and  passes  in  front  of  the  aorta. 

•T    Supra-renal, — on  the  right  side  ends  in  the  vena  cava,  on  the  left  side  in 
f^      the  left  renal  or  phrenic  vein. 

Phrenic  2, — the  superior  ends  in  the  internal  mammary,  the  inferior  ends 
oh "the  right  side  in  the  vena  cava,  on  the  left  side  in  the  left  renal  vein. 
Hj&atic  Veins  (16), — begin  in  the  capillary  terminations  of  the  portal 
vein  and  hepatic  artery  in  the  substance  of  the  liver,  uniting  into  3 
large  veins  from  the  right  and  left  lobes  and  the  lobulus  Spigelii,  which 
open  into  the  inferior  vena  cava.  They  have  no  valves. 

The  Portal  System  is  formed  by  the  Superior  and  Inferior  Mesenteric, 
Splenic,  and  Gastric  Veins,  which  collect  the  blood  from  the  digestive  vis- 
cera, and  by  their  union  behind  the  head  of  the  pancreas  form  the  Portal 
Vein,  which  enters  the  transverse  fissure  of  the  liver,  where  it  divides  into  2 
branches.  These  again  subdivide,  ramifying  throughout  the  organ, 
therein  receiving  blood  also  from  the  branches  of  the  hepatic  artery. 
Its  minute  ramifications  end  in  capillaries,  from  which  the  blood  of  the 
portal  system,  together  with  that  brought  by  the  hepatic  artery,  is  carried 
by  the  hepatic  veins  to  the  inferior  vena  cava.  The  portal  vein  generally 
receives  the  Cystic  Vein,  which  sometimes  terminates  in  the  right  branch 
of  the  portaT 


THE    LYMPHATIC    SYSTEM  17 1 

VEINS  OF  THE  HEART  ITSELF 


The  Cardiac  Veins  return  the  blood  from  the  tissue  of  the  heart  into  the 
right  auricle.     They  are  the — 
.    Great  Cardiac  Vein, 

Right  or  Small  Coronary  Vein  (v.  coronaria  ventriculi). 

Posterior  Cardiac  Vein.  S    Anterior  Cardiac  Veins. 


Coronary  Sinus  is  a  dilatation  of  the  great  cardiac  vein,  receiving  the 


Left  Cardiac  Veins.  -^    Ven(B  Thebesii. 

Coronary  Sinus  is  a  dilatation  of  the  great  can 
*    posterior  cardiac  and  an  oblique  vein  from  the  left  auricle. 

THE  LYMPHATIC  SYSTEM 


Lymphatics  are  very  delicate,  transparent  vessels;  the  larger  having  3 
coats  like  the  arteries  and  veins,  the  smaller  having  2  coats,  the  external 
and  internal,  but  no  middle  muscular-elastic  coat.  Lymphatics  are  found 
in  nearly  every  texture  and  organ  of  the  body  which  contains  blood- 
vessels, but  are  absent  in  the  non-vascular  structures,  as  cartilage,  nails, 
cuticle  and  hair.  They  are  nourished  by  blood-vessels  distributed  to  their 
outer  and  middle  coats,  in  which  also  many  non-medullated  nerve-fibres 
have  been  traced.  They  possess  valves  of  semilunar  form,  placed  at 
much  shorter  intervals  than  are  the  valves  in  the  veins.  They  convey 
lymph  to  the  blood,  and  possess  the  property  of  absorbing  certain  materials 
from  the  tissues  and  conveying  them  into  the  circulation;  hence  they  are 
also  called  absorbents.  They  discharge  their  contents  into  the  blood  at 
two  points,  the  junctions  of  the  subclavian  and  internal  jugular  veins,  on 
the  left  side  by  the  thoracic  duct,  on  the  right  side  by  the  right  lymphatic 
duct. 

Lacteals  are  the  lymphatic  vessels  of  the  small  intestine,  conveying  chyle 
to  the  blood  during  the  process  of  digestion. 

Lymphatic  Glands  (lymphoglandulas)  are  small,  solid,  glandular  bodies, 
placed  in  the  course  of  the  lymphatic  and  lacteal  vessels,  and  found 
chiefly  along  the  great  blood-vessels,  at  the  root  of  the  lungs,  in  the  lumbar 
and  cceliac  regions  of  the  abdomen,  in  the  mesentery,  the  mediastina,  the 
head,  neck,  axilla,  groin,  and  popliteal  space.  They  are  named  after  the 
respective  regions  in  which  they  are  situated,  as  axillary  glands,  the 
inguinal,  cceliac,  bronchial,  mesenteric,  etc.  They  consist  of  a  fibrous 
capsule,  from  which  trabecula  are  prolonged  inward,  dividing  the  gland 
into  alveoli  or  open  spaces  containing  lymphoid  tissue,  the  proper  gland- 
substance,  which  is  so  placed  as  to  leave  a  channel  (sinus),  the  lymph- 


172  HUMAN    ANATOMY 

path,  all  around  it.     The  glands  are  nourished  by  blood-vessels  supported 
on  the  trabeculae,  and  some  fine  nerve  filaments  are  traced  into  them. 

Before  entering  a  gland  the  lymphatic  (or  lacteal)  divides  into  several 
small  branches,  the  afferent  vessels,  of  which  the  endothelial  layer  only  enters 
the  gland,  to  form  in  its  lymph-sinuses  a  plexus  of  vessels  which  unite  into 
a  single  efferent  vessel.  The  external  coat  of  the  afferent  vessels  becomes 
continuous  with  the  capsule  of  the  gland,  and  is  received  upon  the  efferent 
vessel  as  it  emerges. 

Haemal  Lymph  Glands, — resemble  ordinary  lymph  glands  in  all  respects 
save  that  some  of  their  sinuses  contain  blood. 

Haemal  Glands, — all  of  their  sinuses  contain  blood,  otherwise  they  do 
not  differ  from  regular  lymph  glands.  Both  Haemal  glands  and  Haemal 
Lymph  glands  are  more  numerous  in  the  retro-peritoneal  tela  along  the 
line  of  the  aorta. 

f/  .  3^  The  Thoracic  Duct  (ductus  thoracicus)  is  the  main  channel  for  the  lymph 
and  chyle  from  the  whole  body  except  the  right  arm  and  lung,  right  side 
of  the  head,  heart,  neck,  and  thorax,  and  the  convex  surface  of  the  liver. 
It  begins  in  the  abdomen  by  a  triangular  dilatation,  the — 

Receptaculum  Chyli  (cisternachyli),  in  front  of  the  zd  lumbar  vertebra, 
passes  through  the  aortic  opening  in  the  diaphragm,  and  opposite  the  7th 
cervical  vertebra  it  curves  forward,  outward  and  downward  over  the 
subclavian  artery,  so  as  to  form  an  arch,  and  terminates  in  the  left  sub- 
clavian vein  at  its  angle  of  junction  with  the  left  internal  jugular  vein.  In 
the  thorax  it  lies  in  the  posterior  mediastinum  in  front  of  the  vertebral 
column,  between  the  aorta  on  its  left  and  the  vena  azygos  major  on  its 
right.  It  has  numerous  valves  throughout  its  course,  and  a  pair  of  valves 
at  its  termination  to  prevent  the  passage  of  venous  blood  into  its  cavity. 

The  Right  Lymphatic  Duct  (ductus  lymphaticus  dexter)  is  a  short  trunk, 
about  2^2  inch  in  length  and  i%  line  in  diameter.  It  terminates  in  the 
right  subclavian  vein  at  its  angle  of  junction  with  the  right  internal 
jugular,  its  orifice  being  guarded  by  two  semilunar  valves  against  the 
passage  of  venous  blood  into  its  cavity.  It  receives  lymph  from  those 
parts  which  are  not  connected  with  the  thoracic  duct,  namely — the  right 
upper  extremity,  the  right  lung,  the  right  side  of  the  head,  neck,  heart 
and  thorax,  and  part  of  the  convex  surface  of  the  liver. 

LYMPHATICS  OF  THE  HEAD  AND  NECK 

Lymphatic  Glands  of  the  Head  and  Neck,  are  as  follows: — • 

Occipital  (lymphoglandulae  occipitales),  i  or  2, — at  the  back  of  the  head, 
close  to  the  artery. 


LYMPHATICS    OF    THE    UPPER    EXTREMITY  173 

Posterior  Auricular  or  Mastoid  (lymphoglandulae  auriculares  posteriores), 

2, — near  the  mastoid  process. 
Anterior  Auricular  (lymphoglandulae  auriculares  anteriores), — external  to 

the  parotid  gland. 
Parotid  (lymphoglandulae  parotideae), — some  in  and  others  around  the 

parotid  gland. 

Buccal,  i  or  more, — on  the  surface  of  the  buccinator  muscle. 
Submandibular  (lymphoglandulae  submaxillares), — beneath  the  ramus  of 

the  jaw. 
Lingual  (lymphoglandulae  linguales),   2   or  3, — on  the  hyo-glossus  and 

genio-hyo-glossus  muscles. 
Retro-pharyngeal  (lymphoglandulae  retropharyngeae)   2, — one  on  each  side 

of  the  middle  line. 
Superficial  Cervical  (lymphoglandulae  cervicales  superficiales), — consisting 

of  the  submaxillary,  8  to  10,  the  suprahyoid,  i  or  2,  and  the  cervical 

(many)  in  the  course  of  the  external  jugular  vein. 
Deep  Cervical  (lymphoglandulae  cervicales  profundae   superiores  et  infe- 

riores), — forming  a  chain  along  the  sheath  of  the  carotid  artery  and  in- 
ternal jugular  vein,  in  two  sets,  an  upper,  10  to  20,  and  a  lower,  10 

to  15. 

Lymphatic  Vessels  of  the  Head  and  Neck  are — the/  Temporal  and 
;  Occipital,  in  the  scalp,  respectively  accompanying  the  temporal  jand  oc- 
cipital arteries;  the  'Meningeal  an^  Cerebral,  in  the  cranium;  the  Super- 
ficial and  the  Deep,  in  the  face;  also  those  of  the  orbit,  the  temporal  and 
zygomatic  fossae,  the  nose,  tongue,  pharynx,  larynx  and  thyroid  body. 
In  the  neck  these  vessels  are  continuations  of  those  on  the  cranium  and 
face. 

LYMPHATICS  OF  THE  UPPER  EXTREMITY 

Lymphatic  Glands  of  the  Upper  Extremity  (lymphoglandulae  cubitales 
superficiales  et  profundae)  are  in  two  sets,  the  Superficial,  which  are  few 
and  small,  and  ih^Deep,  in  the  forearm,  the  "arm  and  the  axilla.  The 
Axillary  Glands,  10  to  12,  are  of  large  size,  situated  around  the  axillary 
vessels,  in  the  tissue  of  the  axilla,  and  in  chains  along  the  lower  border  of 
the  pectoralis  major  muscle  and  the  lower  margin  of  the  posterior  wall  of 
the  axilla,  they  are  grouped  as  follows: — 

1.  Brachial   or  lateral. 

2.  Subscapular  or  posterior. 

3.  Pectoral  or  anterior. 

4.  Central. 

5.  Subpectoral. 


174  HUMAN    ANATOMY 

6.  Infraclavicular. 

7.  Interpectoral. 

8.  Deltopectoral.     (Robinson.) 

Lymphatic  Vessels  of  the  Upper  Extremity  are  the  Superficial,  beginning 
on  the  sides  of  the  fingers  and  accompanying  the  veins;  the^Deep,  occurring 
in  4  sets  corresponding  with  the  radial,  ulnar,  and  anterior  and  posterior 
interosseous  arteries. 

LYMPHATICS  OF  THE  LOWER  EXTREMITY 

Lymphatic  Glands  of  the  Lower  Extremity  are  the — -Superficial  Inguinal, 
8  to  10,  in  two  sets,  an  upper  oblique  set  (lymphoglandulae  inguinales) 
along  Poupart's  ligament  (1.  inguinale),  and  an  inferior  vertical  set  (lympho- 
glandulae subinguinales),  2  to  5,  around  the  saphenous  opening  in  the  fascia 
lata;  Deep  Glands  are  the  anterior  tibial  popliteal  (lymphoglandulae 
popliteae),  deep  inguinal  (lymphoglandulae  subinguinales  profundae), 
gluteal  and  ischiatic. 

Lymphatic  Vessels  of  the  Lower  Extremity  are  in  two  sets,  superficial 
and  deep.  The  Superficial  lie  in  the  superficial  fascia  in  two  groups,  an 
internal  and  an  external,  along  the  internal  and  external  saphenous  veins 
respectively.  The  Deep  are  few  in  number  and  accompany  the  deep  blood- 
vessels. 

LYMPHATICS  OF  THE  PELVIS  AND  ABDOMEN 

Lymphatic  Glands  are  the  external  iliac,  internal  iliac,  and  sacral,  in  the 
pelvis;  and  the  lumbar  and  cceliac  glands  in  the  abdomen.  The  Lumbar 
Glands  are  numerous,  situated  in  front  of  the  lumbar  vertebrae,  and  sur- 
round the  common  iliac  vessels,  the  aorta  and  the  vena  cava.  The  Cceliac 
Glands  20,  surround  the  cceliac  axis  and  lie  in  front  of  the  aorta,  receiving 
the  lymphatic  vessels  from  a  large  part  of  the  liver,  the  spleen,  pancreas 
and  stomach. 

Lymphatic  Vessels  of  the  Pelvis  and  Abdomen  are  in  3  sets,  the  super- 
ficial, the  deep,  and  those  of  the  viscera.  The  Superficial  follow  the  course 
of  the  superficial  blood-vessels,  and  include  the  lymphatics  of  the  gluteal 
region,  the  penis,  scrotum  and  perinaeum.  The  Deep  follow  the  course  of 
the  principal  blood-vessels.  Those  of  the  Viscera  are  the  lymphatics  of 
the  various  organs  contained  in  these  cavities — the  bladder,  rectum, 
uterus,  kidney,  liver,  stomach,  spleen  and  pancreas,  and  include  those  of 
the  testicles. 

LYMPHATICS  OF  THE  INTESTINES 

Lymphatic  Glands  of  the  Intestines  are  those  of  the  large  intestine, 
which  are  few  in  number,  especially  along  the  transverse  colon;  and  those 


LYMPHATICS    OF    THE    THORAX  175 

of  the  small  intestine,  100  to  150,  which  lie  between  the  layers  of  the 
mesentery  and  are  called  the  Mesenteric  Glands  (lymphoglandulae  mesen- 
tericae). 

Lymphatic  Vessels  of  the  Intestines  are  those  of  the  large  intestine, 
some  of  which  enter  the  mesenteric  glands,  others  the  lumbar  glands;  and 
those  of  the  small  intestine,  called  the  Lacteals,  from  the  milk-white  fluid 
(chyle)  which  they  usually  contain.  The  lacteals  are  in  two  sets,  super- 
ficial and  deep,  the  latter  occupying  the  submucous  tissue  and  coursing 
transversely  around  the  intestine. 

LYMPHATICS  OF  THE  THORAX 

Lymphatic  Glands  of  the  Thorax  are  those  of  the  thoracic  walls  (lym- 
phoglandulae sternales  et  intercostales)  and  those  of  the  viscera.  The 
former  are  the  intercostal,  the  internal  mammary,  and  the  anterior  and 
posterior  mediastinal  (lymphoglandulae  mediastinales  anteriores  et 
posteriores)  glands;  the  latter  are  the  bronchial  and  the  superior  medias- 
tinal or  cardiac  glands.  The  — 

Bronchial  Glands  (lymphoglandulae  bronchiales),  10  to  12,  —  are  situated 
around  the  bifurcation  of  the  trachea  and  the  roots  of  the  lungs. 

Superior  Mediastinal  or  Cardiac  Glands,  —  are  numerous  and  large,  lie  in 
front  of  the  transverse  aorta  and  the  left  innominate  vein,  and  receive 
the  lymph  from  the  pericardium,  the  heart,  and  the  thymus  gland. 

Lymphatic  Vessels  of  the  Thorax  are  the  superficial,  the  deep  and  those 
of  the  viscera  in  the  thoracic  cavity.  The  Superficial  converge  to  the 
axillary  glands;  the  Deep  are  the  intercostal,  the  internal  mammary  and  the 
diaphragmatic;  those  of  the  Viscera  are  the  lymphatic  vessels  of  the  lungs, 
heart,  thymus  gland  and  oesophagus. 

THE  NERVOUS  SYSTEM 

/  i.  Brain. 

i.  Central  part       <        _.  .     .  _      , 
[  2.  Spinal  Cord. 

J  i.  Cranial  Nerves. 
..  Penpheral  part 


"   \  2.  Sympathetic  System  (  '"  £anglia'  . 

(  2.  Communicating  Branches. 

Nervous  Tissue  is  formed  of  two  different  structures,  viz.  Gray  or  cineri- 
tious  substance,  in  which  nervous  impressions  and  impulses  originate;  and 
White  or  fibrous  substance,  by  which  the  impressions  and  impulses  are 
conducted.  Chemically,  nervous  tissue  consists  of  proteids,  neurokeratin, 


i76 


HUMAN    ANATOMY 


nucleiii,  protagon,  lecithin,  cerebrosides,  cholesterin,  nitrogenous  ex- 
tractives and  salts,  with  some  gelatin  and  fat,  and  water;  the  latter  varying 
in  different  parts  of  the  system,  from  60  per  cent,  in  the  sciatic  nerve,  to 
70  per  cent,  in  the  white  matter  of  the  cerebrum,  and  83  per  cent,  in  the 
gray  matter  of  the  same  region. 

Gray  Nervous  Substance,  the  essential  constituent  of  all  the  ganglionic 
centres,  is  composed  of  nerve-cells  or  ganglionic  corpuscles,  containing  nuclei 

FIG.  70. 


SHOWING  SOME  OF  THE  VARIETIES  OF  THE  CELL-BODIES  OF  THE  NEURONES  OF 
THE  HUMAN  NERVOUS  SYSTEM,  INCLUDING  THE  DENDRITES  AND  SMALLL  PORTIONS 
OF  THE  AXONES.  AxoNE  SHEATHS  NOT  INCLUDED.  (Morris'  Anatomy.) 

A,  From  spinal  ganglion.  B.  From  ventral  horn  of  spinal  cord.  C.  Pyramidal 
cell  from  cerebral  cortex.  D.  Purkinje  cell  from  cerebellar  cortex.  E.  Golgi  cell  of 
type  II  from  spinal  cord.  F.  Fusiform  cell  from  cerebral  cortex.  G.  Sympathetic. 
a,  axone;  d,  dendrites;  c,  collateral  branches;  ad,  apical  dendrites;  bd,  basal  den- 
drites;  c,  central  process ;  p,  peripheral  process. 

and  nucleoli.  The  cells  are  imbedded  in  a  ground  substance,  neuroglia, 
which  consists  of  fibres  and  cells,  and  is  a  connective  tissue  in  function 
though  not  in  development.  A  neurone  is  a  nerve-cell  together  with  all 
of  its  processes.  Nerve-cells  vary  in  size  and  shape,  and  possess  one  or 
more  processes,  according  to  the  number  of  which  they  are  grouped  into 
unipolar,  bipolar  and  multipolar  cells.  Of  these  processes  one  is  called  the 


THE   NERVOUS   SYSTEM  177 

axone  or  axis-cylinder  process,  because  it  becomes  the  axis-cylinder  of  a 
nerve- fibre;   the  others  are  termed  dendrltes  or  protoplasmic  processes. 

White  Nerve  Substance  or  Nerve-fibre,  contains  two  kinds  of  fibres, 
the  medullated  or  white  and  the  non-medullated  or  gray.  Medullated 
Fibres  contain  a  central  core  or  axis-cylinder,  the  essential  part  of  the 
nerve-fibre,  and  regarded  as  a  direct  prolongation  of  a  nerve-cell.  This  is 
surrounded  by  the  medullary  sheath,  or  white  substance  of  Schwann,  com- 
posed of  fatty  matter  in  a  fluid  state,  which  insulates  and  protects  the 
axis-cylinder.  These  are  enclosed  in  the  primitive  sheath  or  neurilemma, 
sometimes  called  the  tubular  membrane  or  sheath  of  Schwann,  which  is 
absent  in  the  fibres  found  in  the  brain  and  spinal  cord.  A  bundle  or 
funiculus,  of  such  fibres,  held  together  by  endoneurium,  is  surrounded  by 
perineurium,  both  formed  of  delicate  connective  tissue;  and  several  funic- 
uli  are  collected  into  larger  bundles,  fasciculi,  which  are  bound  together 
by  a  common  membrane,  the  epineurium,  and  then  are  called  a  Nerve, 
The  whole  arrangement  is  precisely  analogous  to  that  of  a  submarine  tele- 
graph cable.  The  nerve  is  nourished  by  a  minute  system  of  capillary 
blood-vessels,  and  has  certain  medullated  fibres  in  the  epineurium,  termed 
the  nervi  nervorum,  or  nerves  of  the  nerves. 

The  Non-medullated  Fibres,  also  called  gray  or  gelatinous  nerve-fibres,  or 
fibres  of  Remak,  consist  of  a  central  core-  or  axis-cylinder  enclosed  in  a 
nucleated  sheath.  They  constitute  most  of  the  sympathetic  nerves  and 
include  some  of  the  cerebro-spinal. 

Terminations  of  Nerves.  Their  origin  or  central  termination  occurs 
from  the  nerve  centre  by  one  or  two  roots,  in  the  latter  case  sometimes 
widely  apart  from  each  other.  The  efferent  nerve-fibres  originate  in 
the  cells  of  the  gray  substance,  the  afferent  fibres  branch  among  the  cells 
without  uniting  with  them.  The  peripheral  termination  of  sensory  nerves 
seems  to  be  in  minute  primitive  fibrilla  or  networks  thereof;  that  of  motor 
nerves  in  special  terminal  organs,  variously  named,  as  the  end-bulbs 
of  Krause,  the  tactile  corpuscles  of  Wagner,  the  Pacinian  corpuscles, 
the  neuro-tendinous  and  neuro-muscular  spindles,  and  the  motorial  end- 
plates  of  the  striped  or  voluntary  muscular  fibre. 

Ganglia  are  separate  small  aggregations  of  nerve-cells,  connected  with 
each  other,  with  the  cerebro-spinal  axis,  and  with  nerves  in  various 
situations.  They  consist  of  a  collection  of  nerve-cells  and  nerve-fibres, 
invested  by  a  membranous  envelope,  which  is  continuous  with  the  peri- 
neurium of  the  nerves,  and  sends  processes  into  the  interior  of  the  ganglion 
to  support  the  blood-vessels  supplying  its  substance.  They  are  found  on 
the  posterior  roots  of  all  the  spinal  nerves,  on  the  posterior  (sensory)  root 
12 


178  HUMAN   ANATOMY 

of  the  5th  cranial  nerve;  on  the  facial,  auditory,  glosso-pharyngeal  and 
pneumogastric  nerves;  also  in  a  connected  series  along  each  side  of  the 
vertebral  column  anteriorly,  forming  the  trunk  of  the  sympathetic,  and 
on  the  branches  of  that  nerve. 

THE  BRAIN 

Development  of  the  Brain.  At  an  early  period  of  embryonic  life  the 
cerebro-spinal  axis  consists  of  a  thin-walled  tube,  the  neural  tube,  which, 
while  still  open  at  its  caudal  end,  becomes  enlarged  at  its  cephalic  end, 
where  constrictions  appear,  dividing  this  end  into  3  primary  vesicles, 
the  anterior,  middle  and  posterior.  From  these  vesicles  are  developed  the 
ventricles  of  the  brain,  the  rest  of  the  neural  tube  forming  the  central 
cavity  of  the  spinal  cord.  Thickenings  of  the  wall  of  the  neural  tube 
form  the  substance  of  the  brain  and  spinal  cord.  The — • 

Anterior  Primary  Vesicle,  Prosencephalon, — divides  into  an  anterior 
(telencephalon)  and  a  posterior  (diencephalon]  secondary  vesicles. 
From  the  telencephalon  are  developed  the  cerebral  hemispheres; 
corpora  striata;  corpus  callosum;  fornix;  lateral  ventricles; 
olfactory  lobe;  front  part  of  the  third  ventricle;  front  part  of  the 
tuber  cinereum;  infundibulum;  and  the  posterior  lobe  of  the  pituitary 
body  (hypophysis).  From  the  diencephalon  are  developed,  the  optic 
thalami  (thalamus);  corpora  geniculata  (metathalamus) ;  pineal 
body,  the  posterior  part  of  the  tuber  cinereum;  posterior  part 
of  the  third  ventricle;  corpora  mammillaria;  optic  nerve  and 
optic  tracts. 

Middle  Primary  Vesicle,  Mesencephalon, — its  cavity  becomes  the 
aqueduct  of  Sylvius,  and  with  the  parts  developed  around  it  con- 
stitutes the  mesencephalon  or  mid-brain.  From  the  mesencephalon 
are  developed,  corpora  quadrigemina;  pedunculi  (crura)  cerebri; 
and  aquaeductus  cerebri  (aquaeduct  of  Sylvius). 

The  constricted  communication  between  the  middle  primary  vesicle 
and  the  posterior  primary  vesicle  is  known  as  the  isthmus  rhomben- 
cephali,  from  it  are  developed  the  superior  cerebellar  peduncles 
(brachia  conjunctiva)  and  the  valve  of  Vieussens  (anterior  medullary 
velum). 

Posterior  Primary  Vesicle,  Rhombencephalon, — by  constriction  forms 
an  anterior  secondary  vesicle,  metencephalon;  and  a  posterior  second- 
ary vesicle,  myelenccphalon. 

From  the  metencephalon  are  developed  the  cerebellum;  pons  varolii 
(pons) ;  and  front  part  of  the  fourth  ventricle. 


THE  BRAIN  179 

From  the  myelencephalon  are  developed   the  medulla  oblongata  and 

the  posterior  portion  of  the  fourth  ventricle. 

Structure  of  the  Cerebrum.  The  cerebrum  is  composed  of  gray  and 
white  matter,  the  former  disposed  in  two  great  groups, — that  of  the  cere- 
bral cortex  and  that  in  the  basal  ganglia. 

The  Gray  Matter  of  the  Cortex  is  composed  of  6  alternating  white  and 
gray  layers.  The  cortex  is  made  up  of  nerve-cells  and  nerve-fibres.  The 
Nerve-cells  are  arranged  in  5  layers,  named,  from  the  surface  inward,  as 
follows:  the  fmolecular  layer,  the  outer  layer  /'.of  polymorphous  cells,  the 
layer  of  small  pyramidal  cells,  the  layer  of  large  pyramidal  cells,  the  inner 
layer  of  polymorphous  cells.  In  certain  parts  of  the  cortex  this  arrange- 
ment is  variously  departed  from,  as  many  as  9  layers  being  described  in 
the  cuneus.  The  Nerve-fibres  are  either  medullated  fibres  or  naked  axis- 
cylinders  embedded  in  a  matrix  of  neuroglia. 

The  Basal  Ganglia  are  a  series  of  gang! ionic  masses  in  the  base  of  each 
cerebral  hemisphere,  subjacent  to  the  island  of  Reil,  they  and  it  constitut- 
ing the  oldest  part  of  the  hemisphere,  the  first  to  appear  in  the  order  of 
development.  They  are  semi-detached  local  thickenings  of  the  gray 
cortex,  and  are  named  as  follows: — 

Corpus  Striatum, — composed  of  two  nuclei,  the  caudate  and  the  len- 
ticular (lentiform)  (described  on  page  191).     Closely  associated  with 
it  are  certain  fasciculi  of  white  matter,  the — /  £3cr/ 
Internal  Capsule  (page  192). 
External  Capsule  (page  192). 
Anterior  Commissure  (page  192). 
Tania  Semicircularis  (stria  terminalis)  (page  190). 
Claustfum, — a  thin  band  of  gray  matter,  described  under  the  corpus 

striatum  on  page  191. 

Nucleus  Amygdala, — a  thickening  of  the  cortex  of  the  apex  of  the 
temporal  lobe,  producing  a  bulge,  the  amygdaloid  tubercle,  in  the  roof 
of  the  extremity  of  the  descending  cornu  of  the  lateral  ventricle. 
The  Optic  Thalamus,  though  in  close  proximity  to  the  corpus  striatum, 
is  not  placed  among  the  basal  ganglia  of  the  hemispheres,  being  considered 
part  of  the  diencephalon  or  inter-brain. 

The  White  Matter  consists  of  medullated  fibres  in  bundles,  arranged  in 
the  following  3  systems: — 

PROJECTION  FIBRES  (peduncular), — connecting  the  hemispheres  with 
the  medulla  oblongata  and  the  cord.  They  originate  in  the  cells  of 
the  cerebral  cortex  from  whence  they  proceed,  forming  the  corona 
radiata  as  they  converge  to  enter  the  internal  capsule  when  they  are 


l8o  HUMAN    ANATOMY 

collected  into  the  several  bundles  which  are  continued  as  the  crusta 
(basis)  of  the  crura  (pedunculi)  cerebri. 

TRANSVERSE  OR  COMMISSURAL  FIBRES, — connect  the  two  hemispheres. 
They  are  the  transverse  fibres  of  the  corpus  callosum,  and  the  anterior 
and  posterior  commissures  of  the  3d  ventricle. 

ASSOCIATION  FIBRES, — connect  different  structures  in  the  same  hemi- 
sphere; the  short  connecting  adjacent  convolutions;  and  the  long, 
connecting  distant  structures,  as  follows,  the— 

Uncinate  Fasciculus, — from  the  frontal  to  the  temporal  lobe, 
across  the  bottom  of  the  fissure  of  Sylvius,  (fissura  cerebri 
lateralis). 

Cingulum, — antero-posteriorly  in   the   convolution  of   the  corpus 

callosum,  from  the  anterior  perforated  substance  to  the  hook 

of  the  uncinate  gyrus  (anterior  end  of  the  sup.  occipito-temporal 

gyrus). 

Superior  Longitudinal  Fasciculus, — connects  the  frontal  lobe  with 

the  occipital  and  temporal  lobes. 

Inferior   Longitudinal  Fasciculus, — connects  the  temporal  with  the 
occipital'lobe.     It  runs  the  entire  length  of  both  lobes  and  con- 
nects their  convolutions. 
Perpendicular  Fasciculus, — connects  the  inferior  parietal  lobule  with 

the  inferior  occipito-temporal  convolution  (gyrus  fusiformis). 
Fornix, — connects  the  hippocampal  convolution  (superior  occipito- 
temporal)  with  the  corpora  albicantia    (corpora   mammillaria) 
and  the  optic  thalamus.. 

THE  MENINGES 

Membranes  of  the  Brain  are  the  dura  mater,  the  arachnoid  membrane, 
and  the  pia  mater. 

—  3  7  The  Dura  Mater  is  a  dense  fibrous  membrane  lining  the  interior  of  the 
skull.  It  consists  of  two  layers  which  are  coalesced  throughout  the 
greater  part  of  their  extent.  The  inner  layer  which  is  produced  into  the 
intervals  between  parts  of  the  brain  forming  partitions,  and  the  outer 
layer  which  is  strongly  attached  at  the  base  of  the  cranial  cavity  and 
along  the  cranial  sutures  into  which  it  sends  processes.  The  outer 
layer  forms  the  internal  periosteum  of  the  cranial  bones.  It  is  con- 
tinuous with  the  dura  mater  of  the  spinal  cord,  with  the  pericranium, 
and  the  periosteum  of  the  orbit;  being  prolonged  to  the  outer  surface  of 
the  skull  through  the  various  foramina  at  its  base.  It  sends  4  processes 
into  the  cavity  of  the  skull  for  the  support  of  the  different  parts  of  the 
brain,  also  several  tubular  processes  and  prolongations  through  orifices  and 


THE    MENINGES  l8l 

foramina  in  the  skull  for  the  protection  of  nerve  trunks  and  vessels.  The 
Cerebral  dura  mater  derives  its  nerve  supply  from  the  4th  and  5th  cranial 
nerves,  and  from  the  sympathetic  (Whitaker).  It  presents  the  following 
points  for  examination — 

Tht  Mcningeal  Arteries, — are  on,  or  close  to,  the  outer  surface,  whereas 

the   veins  are  deeply    placed    between    the    two   layers   and  form 

sinuses  (see  page  164). 
Falx  Cerebri, — an  arched  process  into  the  longitudinal  fissure  of  the  brain 

vertically;  contains  in  its  upper  and  lower  margins  the  superior  and 

inferior  longitudinal  sinuses. 
Tentorium  Cerebelli, — a  lamina  of  dura  mater  supporting  the  posterior 

lobes  of  the  brain,  and  covering  the  upper  surface  of  the  cerebellum. 

It  incloses  the  lateral  and  superior  petrosal  sinuses. 
Falx  Cerebelli, — projects  between  the  lateral  lobes  of  the  cerebellum, 

from  the  tentorium  to  the  foramen  magnum. 
Diaphragma  Sella, — a  horizontal  process  forming  a  small  circular  fold 

which  almost  covers  the  pituitary  body  and  constitutes  a  roof  for  the 

sella  turcica. 
Pacchionian  Bodies  (granulationes  arachnoideales), — clusters  of  white 

granulations  situated  on  both  the  outer  and  inner  surface  of  the  dura 

mater  near  the  larger  sinuses,  and  in  the  interior  of  the  larger  sinuses 

(see  page  182). 

The  Arachnoid  Membrane  is  a  delicate  single-layer  envelope  which 
covers  the  brain,  lying  between  the  dura  mater  and  the  pia  mater,  although 
throughout  a  large  part  of  its  extent  it  is  not  distinct  from  the  pia  mater. 
It  is  separated  from  the  dura  mater  by  the  superficial  cerebral  veins.     It 
dips  into  the  great  longitudinal  fissure  of  the  brain  and  into  the  interval 
between  the  cerebrum  and  cerebellum  but  it  does  not  enter  the  fissures 
between  the  convolutions  of  the  brain.     Processes  of  it  are  prolonged 
around  the  cranial  nerves  as  far  as  their  points  of  exit  from  the  skull.     It 
is  supplied  probably  by  the  5th,  7th  and  nth  cranial  nerves  (Whitaker). 
Subdural  Space  (cavum  subdurale), — is  the  space  between  the  arach- 
noid and  the  dura  mater.     It  contains  a  small  amount  of  fluid  of  the 
nature  of  lymph. 

Subarachnoid  Space  (cavum  subarachnoidalis), — is  the  interval  between 
the  arachnoid  and  pia  mater,  forming  the  two  large  spaces,  mentioned 
below,  at  the  base  of  the  brain,  but  small  on  the  surface  of  the  hemi- 
spheres. It  is  occupied  by  a  spongy  connective  tissue,  in  the  meshes 
of  which  the  cerebro-spinal  fluid  is  contained.  It  communicates  with 
the  genera]  ventricular  cavity  of  the  brain  by  3  openings,  one  of 


1 82  HUMAN    ANATOMY 

which,  the  foramen  of  Magendie  (metapore),  is  in  the  middle  line  at 
the  lower  end  of  the  roof  of  the  4th  ventricle. 

Anterior  Subarachnoidean  Space  (cisterna  interpeduncularis), — is  the 
interval  between  the  arachnoid  and  the  pia  mater  at  the  base  of  the 
brain,  where  the  former  membrane  extends  across  between  the  two 
temporal  lobes. 

Posterior  Subarachnoidean  Space  (cisterna  cerebellomedullaris), — is  a 
similar  interval  between  the  hemispheres  of  the  cerebellum  and  the 
medulla  oblongata.  These  two  spaces  communicate  with  each  other 
across  the  inferior  cerebellar  peduncles  (corpores  restiformes). 

Cerebro-spinal  Fluid, — occupies  the  subarachnoid  space  of  the  brain  and 
spinal  cord,  and  also  the  ventricular  cavities  of  the  brain.  Its 
average  quantity  is  about  2  oz.,  being  most  abundant  in  old  persons. 
It  forms  a  water-bed  for  the  protection  of  the  nervous  centres  from 
the  effects  of  concussions. 

Granulationes  Arachnoideales  or  Pacchionian  bodies, — are  numerous, 
small,  granulations,  which  are  not  glandular  in  structure  but 
enlarged  normal  villi  of  the  arachnoid;  found  on  the  outer  and 
inner  surfaces  of  the  dura  mater,  in  the  superior  longitudinal  sinus, 
and  on  the  pia  mater.  They  are  not  usually  found  until  after  the 
7th  year  of  age,  and  are  occasionally  wanting. 

The  Pia  Mater  is  a  vascular  membrane,  supplied  by  branches  of  the  in- 
ternal carotid  and  vertebral  arteries.  It  covers  the  surface  of  the  brain, 
dipping  down  into  all  the  sulci,  and  forms  the  velum  interpositum  (tela 
chorioidea  ventriculi  tertii)  and  choroid  plexus  (plexus  chorioideus 
ventriculi  lateralis)  of  the  lateral  and  4th  ventricles.  It  consists  of  a 
minute  plexus  of  blood-vessels,  held  together  by  a  very  fine  areolar  tissue; 
and  contains  numerous  lymphatic  vessels  and  nerves,  the  latter  being 
derived  from  both  the  cerebro-spinal  and  sympathetic  systems.  Its 
nerve  supply  is  derived  from  3d,  5th,  6th,  7th  and  8th  cranial  nerves  and 
from  the  sympathetic  (Whitaker). 

Weight  of  the  Brain.  Its  average  weight  in  the  male  adult  is  from  1360 
(Smith)  to  1400  (Spitzka)  grammes;  in  the  female  1250  grammes  (Spitzka), 
of  which  the  cerebrum  is  about  seven-eighths. 

Divisions  of  the  Brain.  The  Brain  may  be  divided  into  the  Cerebrum, 
the  Cerebellum,  the  Pons  Varolii  (pons)  and  the  Medulla  Oblongata;  but 
for  the  descriptive  purposes  it  is  best  considered  under  the  following  5 
divisions,  viz.  the — 

Cerebral  Hemispheres  or  Telencephalon, — comprising  the  various  lobes, 
the  lateral  and  5th  ventricles,  and  the  basal  ganglia. 


THE  BRAIN  183 

Inter-brain  or  Diencephalon, — the  region  of  the  3d  ventricle,  including 
also  the  optic  thalami  and  the  pineal  gland. 

Mid-brain  or  Mesen-cephalon, — comprising  the  crura  cerebri,  the  corpora 
quadrigemina,  the  corpora  geniculata,  and  the  aqueduct  of  Sylvius 
(aquaeductus  cerebri). 

Hind-brain  or  Melencephalon, — comprising  the  pons  Varolii,  the  cere- 
bellum, and  the  upper  half  of  the  4th  ventricle. 

Medulla  Oblongata  or  Myelencephalon, — including  the  lower  half  of  the 
4th  ventricle. 

The  Cerebrum  or  Telencephalon.  The  cerebrum  presents  an  ex- 
ternal surface  of  gray  matter  called  the  cortex,  the  large  upper  part 
of  which  is  called  the  Pallium  or  Mantle;  the  smaller  lower  or  basilar 
part  is  called  the  Rhinencephalon.  The  surface  of  the  brain  presents 
numerous  clefts;  some  of  these  clefts  cause  a  corresponding  projec- 
tion into  the  cavities  of  the  interior  of  the  brain  and  are  called 
Fissures  (fissurae)  in  order  to  distinguish  them  from  the  others  called 
Sulci,  which  are  those  clefts  which  separate  lobes  (or  lobules)  from  each 
other.  Clefts  that  separate  the  lobes  from  each  other  are  called 
inter-lobular  sulci,  while  those  that  divide  lobes  into  convolutions  or 
gyri  are  known  as  intra-lobular  sulci.  The  cerebrum  is  divided  into 
two  hemispheres  by  the  Great  Longitudinal  fissure  (fissura  longi- 
tudinalis  cerebri). 

THE  CEREBRAL  HEMISPHERES 

Lobes  in  each  Hemisphere,  are  as  follows: — 
Frontal  Lobe, — bounded  internally  by  the  longitudinal  fissure,  below  by  the 

fissure  of  Sylvius   (fissura  cerebri  lateralis),  and  posteriorly  by  the 

fissure  of  Rolando  (sulcus  cerebri  centralis). 
Parietal  Lobe, — extending  down  to  the  fissure  of  Sylvius  (fissura  cerebri 

lateralis),  and  antero-posteriorly  from  the  fissure  of  Rolando  (sulcus 

cerebri  centralis)  to  the  external  parieto-occipital  fissure. 
Occipital  Lobe, — behind  the  parieto-occipital  fissure. 
Temporal  Lobe, — lying  in  the  middle  fossa  of  the  skull,  and  bounded  in 

front  by  the  fissure  of  Sylvius  (fissura  cerebri  lateralis). 
Central  Lobe,  or  Island  of  Reil  (Insula), — lies  in  the  fissure  of  Sylvius 

(fissura  cerebri  lateralis)  covered  by  the  frontal  and  temporal  lobes. 
Limbic  Lobe, — arches  around  the  corpus  callosum  and  the  hippocampal 

fissure;  is  well  developed  in  animals  having  a  keen  sense  of  smell. 
Olfactory  Lobe, — situated  on  the  under  surface  of  the  frontal   lobe,  and 

divided  into  the  olfactory  bulb,  the  olfactory  tract,  the  trigonum,  and 


184  HUMAN   ANATOMY 

the  posterior  olfactory  lobule  (ant.  perforated  space  or  substantia  per- 
forata  anterior). 

Fissures  of  the  Cerebrum  are  as  follows: — 

Longitudinal  Fissure  (fissura  longitudinalis  cerebri), — extends  from  the 
front  of  the  cerebrum  to  the  back,  separating  it  into  two  hemispheres, 
which  are  connected  in  the  middle  portion  by  the  central  commissure, 
the  corpus  callosum  (10),  forming  the  floor  of  the  fissure  in  this  part  of 
its  length. 

Syhian  Fissure,  or  Fissure  of  Sylvius  (fissura  cerebri  lateralis), — on  each 
side  at  the  base  and  lateral  side  of  the  brain.  Starting  at  the  anterior 
perforated  substance  it  passes  outward  to  the  external  surface  of  the 
hemisphere,  where  it  divides  into  a  short  anterior  limb  (ramus  anterior 
horizontalis),  a  short  ascending  limb  (ramus  anterior  ascendens),  and 
a  horizontal  limb  (ramus  posterior).  It  lodges  the  middle  cerebrav 
artery. 

Fissure  of  Rolando  (sulcus  cerebri  centralis)  (i), — on  the  superior  surface 
of  each  hemisphere,  extending  from  the  longitudinal  fissure  about  it? 
centre,  downward  and  forward  toward  the  fissure  of  Sylvius,  separating 
the  frontal  and  parietal  lobes.  This  fissure  is  said  to  be  found  only  in 
man  and  the  higher  primates. 

Parieto-occipital  Fissure, — extends  from  the  longitudinal  fissure  outward 
for  about  an  inch  between  the  parietal  and  occipital  lobes. 

Calloso-marginal  Fissure  (sulcus  cinguli), — above  the  gyrus  fornicatus 
(gyrus  cinguli)  on  the  inner  surface  of  each  hemisphere. 

Internal  Parieto-occipital  Fissure, — extends  downward  and  forward  to  join 
the  calcarine  fissure,  on  'a  level  with  the  hinder  end  of  the  corpus  cal- 
losum. 

Calcarine  Fissttre  (fissura  calcarina), — begins  close  to  the  posterior  extrem- 
ity of  the  hemisphere,  runs  horizontally  forward,  joined  by  the  parieto- 
occipital  fissure,  and  terminates  a  little  below  the  posterior  end  of  the 
corpus  callosum  (u). 

Collateral  Fissure, — below  and  external  to  the  preceding,  runs  forward 
from  the  posterior  extremity  of  the  brain  nearly  as  far  as  the  tip  of  the 
temporal  lobe. 

Dentate  or  Hippccampal  Fissure, — commences  behind  the  posterior  end 
of  the  corpus  callosum  (n)  and  runs  forward  to  the  recurved  part 
(uncinate  gyrus)  of  the  hippocampal  gyrus  (posterior  horizontal  part 
of  the  sup.  occipi to- temporal  convolution). 

Transverse  Fissure, — a  horse-shoe  shaped  gap  or  cleft  at  the  base  of  the 
brain,  extending  from  the  foramen  of  Munro  on  each  side  to  the  termina- 


THE  BRAIN 


FIG.  71. 


tion  of  the  descending  cornu  of  the  lateral  ventricle.  One-half  the 
fissure  is  in  each  hemisphere,  and  it  admits  an  invagination  of  the  pia 
mater,  which  forms  the  choroid  plexus  in  the  lateral  ventricle  and  the 
velum  interpositum  (tela  chorioidea  ventriculi  tertii)  in  the  3d  ventricle. 
It  gives  exit  to  the  venae  Galeni. 

Parallel  Fissure,  formerly  called  the  first  temporo-sphenoidalfisstire, — on  the 
lateral  surface  of  the  hemisphere  below  the  fissure  of  Sylvius  (fissura 
cerebri  lateralis). 

Cerebral  Convolutions.  The  superior  and  inner  surfaces  of  each  hemi- 
sphere are  formed  of  convolutions  (gyri)  with  intervening  fissures  and  de- 
pressions (sulci)  of  various  depths, 
the  gyri  and  sulci  being  both 
formed  of  gray  matter  thus  ar- 
ranged to  enable  it  to  present  a 
great  extent  of  surface.  The  con- 
volutions are  not  uniform  in  all 
brains  as  to  arrangement,  nor  are 
they  symmetrical  in  the  two 
hemispheres.  The  principal  con- 
volutions are  the  following- 
named  : — 

On  the  Frontal  Lobe  are  8,  ex- 
t  e  r  n  a  1 1  y  —  the  ascending 
(gyrus  centralis  anterior) 
(2),  superior  (4),  middle  (5) 
and  inferior  (6)  frontal;  in- 
feriorly  the  internal,  anterior 
and  posterior  orbital.  The 
inferior  frontal  on  the  left 
side  is  named  the  convolution 
of  Broca  and  is  the  language 
centre. 

On  the  Parietal  Lobe.,  are  4, 
externally — the  ascending 
(gyrus  centralis  posterior) 
(3),  superior  and  inferior 
parietal,  and  the  quadrate  or 

precuneus,  internally.  The  inferior  parietal  is  subdivided  into  the 
supramarginal,  the  angular,  and  postparietal  gyri,  the  latter  (2)  lying 
around  the  posterior  end  of  the  superior  temporal  sulcus  (parallel 
fissure)  (see  above). 


1 86  HUMAN   ANATOMY 

The  Occipital  Lobe  has  4,  externally — the  superior  (7),  middle  (8)  and 
inferior  (9)  occipital;  and  internally  the  cuneate  lobule  or  cuneus. 

Temporal  Lobe  has  5  gyri, — externally,  the  superior,  mfddle,  and 
inferior  temporal  gyri;  below  on  the  tentorial  surface,  the  superior 
occipito-temporal  (gyrus  lingualis  or  subcalcarine),  and  the  inferior 
occipi to- temporal  (gyrus  fusiformis).  Part  of  the  inferior  temporal 
gyrus  also  shows  on  this  surface.  On  the  upper  surface,  two  or  three 
indefinite  gyri  can  be  seen.  The  superior  occipito-temporal  lobe  is  by 
some  considered  to  be  two  lobes,  in  which  case,  its  anterior,  upwardly 
hooked  portion  is  called  the  uncinate  gyrus,  the  posterior  horizontal 
portion  being  called  the  hippocampal  gyrus. 

The  Central  Lobe  or  Island  of  Reil  (insula),  is  subdivided  by  the  sulcus 
centralis  into  the  precentral  lobe  (pars  frontalis)  and  the  postcentral 
lobe  (pars  occipitalis).  The  insula  is  pyramidal  in  shape  and  consists 
of  5  or  6  convolutions  called  gyri  operti. 

Under  Surface  of  the  Base  of  the  Brain,  from  before  backward,  ex- 
cluding the  vessels  and  the  cranial  nerves,  shows  the  following  points  for 
examination.  In  the  middle  line  are  the — 

Longitudinal  Fissure, — its  anterior  portion  separating  the  frontal  lobes, 
and  its  posterior  portion  between  the  occipital  lobes. 

Corpus  Callosum, — the  great  transverse  commissure,  seen  in  the  longi- 
tudinal fissure,  and  showing  its  peduncles,  one  on  each  side,  to  meet 
the  corresponding  outer  root  of  the  olfactory  tract. 

Lamina  Cinerea, — a  thin,  triangular,  gray  layer,  continuous  with  the 
anterior  perforated  space  (locus  perforatus  anterior).  In  the  mid- 
line  it  is  divided  into  a  right  and  a  left  portion  by  a  very  thin  almost 
transparent  portion — the  lamina  terminalis,  which  forms  the  anterior 
and  inferior  boundary  of  the  3d  ventricle. 

Optic  Commissure, — formed  by  the  junction  of  the  optic  tracts. 

Tuber  Cinereum  (17) — a  gray  lamina  behind  the  optic  commissure,  form- 
ing part  of  the  floor  of  the  third  ventricle.  From  it  projects  the — 

Infundibulum, — a  hollow  process,  its  canal  connecting  the  pituitary 
cavity  with  the  3d  ventricle  in  the  foetus. 

Eminentia  Saccularis, — between  the  corpora  albacantia  or  mammillaria 
and  the  tuber  cinereum,  it  is  a  trefoil-shaped  eminence  homologous 
with  the  saccus  vasculosus  of  the  lower  vertebrates. 

The  Pituitary  Body  or  Gland  (Hypophysis  Cerebri), — is  a  small  oval  body 
depending  by  the  infundibulum  from  the  tuber  cinereum  in  the  floor 
of  the  third  ventricle.  It  occupies  the  pituitary  fossa  (fossa  hypo- 
physeos)  in  the  sella  turcica  of  the  sphenoid  bone.  It  consists  of  two 


THE  BRAIN 


FIG.  72. 


27 


THE   BASE   OF  THE   BRAIN 

i.  Olfactory  Bulb.  2.  Second,  or  Optic  Nerves.  3.  Anterior  Perforated  Space. 
4.  Optic  Tract.  5-  Crus  Cerebri.  6.  3d  Nerve.  7.  4th  Nerve.  8.  sth  Nerve.  9. 
6th  Nerve.  10.  Pyramid,  n.  Olivary  Body.  12.  Vertebral  Artery.  13.  Anterior 
Spinal  Artery.  14.  Anterior  Cerebral  Artery.  15.  Lamina  Cinerea.  16.  Middle 
Cerebral  Artery.  17.  Tuber  Cinereum.  18.  Corpora  Albicantia.  19.  Posterior 
Perforated  Space.  20.  Posterior  Cerebral  Artery.  21.  Superior  Cerebral  Artery. 
22.  Pons  Varolii.  23.  Inferior  Cerebellar  Artery.  24.  7th  and  Sth  Nerves.  25. 
9th,  loth  and  nth  Nerves.  26.  I2th  Nerve.  27.  Cerebellum. 


1 88  HUMAN    ANATOMY 

lobes.  Anterior  (buccal  or  glandular)  lobe  is  the  larger,  it  secretes 
a  colloid  substance  much  like  that  of  the  thyroid  gland  (glandula 
thyreoidea).  Its  structure  is  much  like  that  of  the  para-thyreoid 
bodies.  It  consists  of  compartments  which  are  lined  with  cuboidal 
cells  of  two  varieties.  The  principal  cells  are  the  more  numerous; 
they  are  small  cells  with  very  granular  cytoplasm.  The  large  cells 
are  chromophile  cells.  The  anterior  lobe  is  derived  from  the  primitive 
buccal  cavity  (stomatodaeum).  Posterior  or  cerebral  lobe  is  the 
smaller  and  is  connected  by  the  infundibulum  to  the  tuber  cinereum, 
but  is  not  known  to  be  functional.  It  is  composed  chiefly  of  neu- 
rogliar  connective  tissue  and  blood-vessels,  throughout  which  are 
interspersed  numerous  branched  cells.  It  has  no  organized  structure. 
It  is  derived  from  the  hypophyseal  diverticulum  of  the  diencephalon. 
The  hypophysis  gets  its  blood  supply  from  the  hypophyseal  branches 
of  the  internal  carotid  artery,  it  is  classed  as  one  of  the  ductless  glands. 

Corpora  Albicantia  (corpora  mammillaria)  (18), — two  round,  white 
eminences,  united  together;  they  are  the  anterior  crura  of  the  fornix 
folded  on  themselves. 

Posterior  Perforated  Space  (Pans  Tarini  or  Substantia  Perforata  Posterior} 
(19), — perforated  for  vessels  to  the  optic  thalami;  forms  part  of  the 
floor  of  the  3d  ventricle. 

Pons  Varolii  (pons)  (22), — a  broad  band  of  white  fibres,  passing  from 
one  cerebellar  hemisphere  to  the  other  described  on  page  203. 

Medulla  Oblongata  (13), — pyramidal  in  form,  emerges  from  the  posterior 

border  of  the  pons  Varolii.      It  is  described  on  page  208, 
On  each  side  of  the  middle  line  are  seen  the — 

Frontal  Lobe, — its  under  surface  (see  ante,  page  185);  lying  thereon  is 
the— 

Olfactory  Lobe, — consisting  of  the  olfactory  bulb  (i),  the  olfactory 
tract,  the  trigonum  olf actorium,  and  the  posterior  olfactory  lobule  or 
anterior  perforated  space  (3). 

Anterior  Perforated  Space  (substantia  perforata  anterior),  (3)  or  pos- 
terior olfactory  lobule, — at  the  commencement  of  the  fissure  of  Sylvius 
(fissura  cerebri  lateralis);  is  perforated  for  small  arteries  going 
to  the  corpus  striatum. 

Fissure  of  Sylvius  (fissura  cerebri  lateralis), — is  described  on  page  184. 

Optic  Tract  (4), — runs  obliquely  across  the  crus  cerebri  as  a  flat  band, 
and  enters  into  the  optic  commissure. 

Crus  Cerebri  or  Cerebral  Peduncle  (5), — a  thick  bundle  of  white  matter 
in  front  of  the  anterior  border  of  the  pons,  passing  forward  and  out- 
ward to  enter  the  undfir  surface  of  the  hemisphere.  The  two  crura 


THE   BRAIN  189 

connect  the  cerebrum  with  the  cerebellum,  medulla  oblongata    and 

spinal  cord.     With  the  optic  tracts  they  form  the  boundaries  of  the 

inter -peduncular  space. 

Temporal  Lobe, — its  under  surface  (see  page  186). 
Cerebellum  (27), — covering  the  occipital  lobe  of  the  cerebrum.     It  is 

described  separately  on  page  206. 

Ventricles  of  the  Brain  are  5  in  number,  of  which  the  two  lateral  and 
the  5th  belong  to  the  cerebral  hemispheres,  the  3d  is  the  cavity  of  the 
interbrain,  and  the  4th  belongs  to  the  cerebellum  and  the  medulla  oblon- 
gata. They  are  situated  as  follows: — 

Two  Lateral  Ventricles,  (ventriculi  laterales), — within  the  substance  of 

the    hemisphere,    one    in  each;    they  are  connected   with   the  3d 

ventricle  and  indirectly  with  each  other  by  the  foramina  of  Munro 

(foramina  interventricularia)  and  the  3d  ventricle. 

Third  Ventricle  (ventriculus   tertius), — a  narrow  crevice  between   the 

optic  thalami,  lying  below  the  lateral  ventricles  and  communicating 

with  them  by  the  foramina  of  Munro  (foramina  interventricularia). 

It  is  connected  with  the  4th  ventricle  by  the  iter  a  tertio  ad  quartum 

ventriculum  or  aqueduct  of  Sylvius  (aquaeductus  cerebri). 

Fourth  Ventricle  (ventriculus  quartus), — between  the  cerebellum  and 

the  medulla  oblongata. 

Fifth  Ventricle  (cavum  septi  pellucidi), — between  the  two  laminae 
of  the  septum  lucidum  (septum  pellucidum),  between  the  two  lateral 
ventricles.  It  is  not  a  true  ventricle. 

The  Lateral  Ventricles  are  two  irregular  cavities  in  the  cerebral  hemi- 
spheres, separated  from  each  other  by  a  partition,  the  septum  lucidum, 
(or  pellucidum),  and  each  having  a  central  cavity  and  3  prolongations  or 
cornua,  the  anterior  in  the  frontal  lobe,  the  middle  in  the  temporal  lobe 
and  the  posterior  in  the  occipital  lobe.  They  communicate  with  each 
other  and  with  the  3d  ventricle  by  the  foramina  of  Munro  (foramina 
interventricularia).  The  central  cavity  (pars  centralis)  is  situated  in  the 
parietal  lobe  and  is  bounded  as  follows: — 

Roof, — the  under  surface  of  the  corpus  callosum. 

Floor, — from   before   backward,    the   caudate   nucleus   of   the   corpus 

striatum,    taenia   semicircularis    (stria    terminalis),    optic  thalamus, 

choroid  plexus,  the  thin  sharp  free  edge  of  the  lateral  half  of  the 

fornix  and  its  posterior  pillar. 

Internally, — the  septum  lucidum   (septum  pellucidum),  separating  it 

from  the  opposite  ventricle. 
Externally,  in  front  and  behind, — brain-substance. 


190  HUMAN    ANATOMY 

Structures  named  above  are  briefly  described  as  follows: — 

Corpus  Callosum, — the  great  transverse  commissure,  arching  backward 
to  become  continuous  with  the  fornix,  reflected  below,  forming  the 
peduncles  at  the  entrance  of  the  fissure  (lateral  cerebral)  of  Sylvius; 
and  marked  above  by  a  depression,  the  Raphe,  and  longitudinal  ele- 
vations, the  stria  longitudinales,  mediates  and  laterales,  or  nerves  of 
Lancisi. 

Septum  Lucidum  (septum  pellucidum), — consists  of  2  layers  of  white 
and  gray  matter,  lined  by  epithelium;  is  placed  vertically  between  the 
lateral  ventricles,  from  the  raphe  of  the  corpus  callosum  above  to 
the  fornix  below.  The  cavity  in  its  centre  is  the  5th  ventricle  (or 
cavum  septi  pellucidi). 

Fornix, — is  a  commissure  situated  beneath  the  corpus  callosum,  but 
continuous  with  it  posteriorly,  the  septum  lucidum  (s.  pellucidum) 
separating  them  in  front.  It  is  composed  of  association  fibres 
which  are  axis-cylinder  processes  connecting  different  parts  of  the 
same  hemisphere.  It  is  of  triangular  form  with  the  apex  in  front. 
Its  anterior  pillars  curve  downward  to  the  base  of  the  brain,  are  there 
reflected,  forming  the  corpora  atticantia  (corpora  mammillaria), 
and  end  in  the  optic  thalami.  Its  posterior  pillars  (crura  fornicis) 
pass  down  the  descending  horns  of  the  lateral  ventricles,  along  the 
concavities  of  the  hippocampi  majores,  and  are  each  continued  as  the 
corpus  fimbrialum  or  t&nia  hippocampi,  into  the  uncus  or  hook  of 
the  hippocampal  convolution.  The  Lyra  (psalterium)  is  a  series  of 
markings  on  its  under  surface. 

Foramina  of  Munro  (foramina  inter ventricularia), — together  form  a 
Y-shaped  opening  situated  between  the  anterior  pillars  of  the  fornix 
in  front  and  above  and  the  anterior  extremities  of  the  optic  thalami 
below  and  behind.  Each  is  crescentic  in  outline  and  by  it  the  lateral 
ventricles  communicate  with  the  3d  ventricle  and  with  each  other. 

Tania  Semicircular  is  (Stria  Terminalis), — consists  of  commissural 
fibres  passing  between  the  corpus  striatum  and  the  optic  thalamu?. 

Choroid  Plexus  of  Veins, — is  the  margin  of  a  fold  of  pia  mater  which 
enters  at  the  transverse  fissure,  passes  up  the  descending  cornu, 
through  the  foramen  of  Munro,  and  as  the  Velum  Interpositum 
(tela  chorioidea  ventriculi  tertii)  spreads  out  over  the  roof  of  the  3d 
ventricle. 

Corpus  Striatum, — is  described  on  page  191. 

Optic  Thalamus, — is  described  on  page  193. 

Cornua  of  the  Lateral  Ventricles.  The  Anterior  Cornu  (cornu  anterius) 
curves  over  the  anterior  end  of  the  corpus  striatum  into  the  frontal  lobe. 


THE   BRAIN  191 

The  Posterior  Cornu  (cornu  posterius)  curves  downward  and  inward  in 
the  occipital  lobe,  and  contains  a  smooth  eminence,  the  Hippocampus 
Minor,  which  is  caused  by  the  calcarine  fissure;  below  thisis  a  slight  eleva- 
tion called  the  calcar  avis.  As  the  calcar  avis  and  the  hippocampus 
diverge  from  each  other  they  leave  a  triangular  interval  called  the  tri- 
gonum  collaterals.  The  Middle  Cornu  (cornu  inferius)  descends  into 
the  temporal  lobe  to  the  transverse  fissure  at  the  base  of  the  brain, 
curving  backward,  outward,  downward,  forward,  and  inward  (initials 
of  the  directions  form  the  mnemonic  word  BODFI).  On  its  floor  are  the 
following: — 

Hippocampus  Major, — a  white  eminence,  about  2  inches  long,  formed 
by  the  infolding  of  the  cerebral  cortex  to  produce  the  dentate  or  hippo- 
campal  fissure. 

Pes  Hippocampi, — the  scolloped  end  of  the  hippocampus. 
Pes  Accessorius  (Eminentia  Collateralis] , — between  the  hippocampi,  at 
the  junction  of  the  middle  and  posterior  cornua,  it  is  caused  by  the 
collateral  fissure. 
Corpus  Fimbriatum, — a  continuation  of  the  posterior  pillar  of  the  fornix 

(crus  fornicis). 

Choroid  Plexus  of  Veins, — a  process  of  pia  mater  (see  page  190). 
Dentate  Convolution   (fascia  dentata), — a  band  of  gray   matter,   just 
below  the  fimbria,  its  free  border  is  notched  by  the  branches  of  the 
choroid  artery. 

Transverse  Fissure  (fissura  chorioidea), — at  the  extremity  of  the  cornu, 
extending  to  the  foramena  of  Munro  (foramena  interventricularia). 
It  is  described  on  page  184. 

The  Fifth  Ventricle  (cavum  septi  pellucidi)  is  a  narrow  chink  situated 
between  the  layers  of  the  septum  lucidum  (septum  pellucidum),  and  there- 
fore lies  between  the  lateral  ventricles.  In  the  ftetus  it  communicates 
with  the  3d  ventricle  by  an  opening  between  the  anterior  pillars  of  the 
fornix  (columnar  fornicis).  Originally  it  was  part  of  the  longitudinal 
fissure  and  was  shut  off  by  the  union  of  the  hemispheres  in  the  formation 
of  the  corpus  callosum  above  and  the  fornix  below.  It  usually  contains 
fluid,  of  the  nature  of  lymph. 

The  Corpus  Striatum  is  a  body  of  gray  matter  imbedded  in  the  white 
substance  of  each  hemisphere,  and  is  partly  seen  in  the  lateral  ventricle 
and  its  anterior  cornu,  this  part  being  the — 

Nucleus  Caudatus  (caudate  nucleus), — the  intra-ventricular  portion;  a 
pear-shaped  mass  having  its  narrow  end  on  the  outer  side  of  the  optic 
thalamus. 


IQ2  HUMAN   ANATOMY 

Nucleus  Lentiformis  (lenticular  nucleus), — the  extra- ventricular  por- 
tion, only  seen  in  sections  of  the  hemisphere.  It  is  divided  by  the 
white  external  and  internal  laminae  into  three  portions,  the  two  medial 
portions  together  constitute  the  globus  pallidus,  the  remaining  part 
is  much  the  larger  and  is  called  the  putamen. 

Internal  Capsule, — a  curved  lamina  of  white  matter  separating  the 
caudate  nucleus  from  the  lenticular  (lentiform)  posteriorly.  It  is 
formed  by  projection  fibres  from  the  crus  cerebri,  the  corpus  stria- 
turn  and  the  optic  thalamus.  [Projection  fibres  are  axis-cylinder 
processes  connecting  cells  in  the  gray  matter  of  the  hemispheres 
with  other  cells  at  lower  levels  in  the  cerebro-spinal  axis.]  Its 
anterior  limb  (pars  frontalis)  is  the  portion  in  front  of  the  curve 
or  genu,  its  posterior  limb  (pars  occipitalis)  lying  behind  the  genu. 

External  Capsule, — a  lamina  of  white  matter  bounding  the  putamen  of 
the  lenticular  (lentiform)  nucleus  externally,  and  made  up  of  asso- 
ciation fibres  from  the  anterior  commissure  and  the  subthalamic 
region. 

Claustrum, — a  thin  layer  of  gray  matter  on  the  outer  surface  of  the 
external  capsule,  regarded  as  a  detached  portion  of  the  gray  matter 
of  the  island  of  Reil  (insula). 

THE  INTER-BRAIN 

The  Inter -brain  or  Thalamen-cephalon  (Diencephalon)  is  the  region 
of  the  3d  ventricle,  and  is  connected  in  front  and  above  with  the  cerebral 
hemispheres,  behind  with  the  mid-brain  or  mesencephalon.  Its  upper 
surface  is  covered  by  iheforrrix;  inferiorly  it  reaches  the  base  of  the  brain, 
it  comprises  the  following  structures, — optic  thalami,  corpora  geniculata 
(metathalamus),  pineal  body  (corpus  pineale),  posterior  part  of  the 
tuber  cinereum,  posterior  part  of  the  third  ventricle,  corpora  albicantia 
(corpora  mammillaria),  optic  nerve,  and  optic  tract. 

The  Third  Ventricle  (ventriculus  tertius)  is  a  mere  fissure,  situated 
in  the  mid-line,  between  the  optic  thalami.  It  communicates  with  the 
lateral  ventricles  above  by  the  foramina  of  Munro  (foramina  interven- 
tricularia)  and  with  the  4th  ventricle  behind  by  the  iter  a  terio  ad 
quartum  ventriculum  (aquaeductus  cerebri).  It  is  crossed  by  3  bands, 
the  anterior,  middle,  and  posterior  commissures,  the  middle  one  being  of 
gray  matter,  the  others  of  white. 

Anterior  Commissure, — is  composed  of  commissural  fibres,  it  appears  to 
connect  together  the  corpora  striata;  its  fibres  are  traced  into  the 
temporal  lobes,  and  include  fibres  from  the  olfactory  tract  of  the 


THE   BRAIN  193 

opposite  side.     Commissural  fibres  are  axis-cylinder  processes  which 

connect  identical  parts  of  the  two  hemispheres. 
Middle  Commissure  (massa  intermedia), — is  composed  of  gray  matter 

and  connects  the  two  optic  thalami. 
Posterior  Commissure, — is  composed  of  commissural  fibres  (see  above);  it 

stretches  across  from  one  optic  thalamus  to  the  other,  and  contains 

fibres  connecting  the  two  thalami,  besides  decussating  fibres  from 

various  parts  of  the  mid-brain. 
Boundaries  of  the  Third  Ventricle  are  as  follows: — 
Roof, — the  velum  interpositum  (tela  chorioidea  ventriculi  tertii),  and 

above  it  the  fornix. 
Floor, — the  parts  comprised  in  the  interpeduncular  space  at  the  base  of 

the  brain,   viz. — the   tuber   cinereum,   with   its  infundibulum   and 

pituitary  body,  corpora  albicantia  (corpora  mammilaria),  posterior 

perforated  space  (substantia  perforata  posterior).     Eminentia  sac- 

cularis,  and  chiasma  optica. 
Anteriorly, — the  anterior  pillars  of  the  fornix  (columnae  fornicis),  and 

the  lamina  terminalis  which  joins  the  right  and  left  half  of  the  lamina 

ceneria. 
Posteriorly, — the  pineal  gland  (corpus  pineale),  posterior  commissure 

and  the  iter  a  terio  ad  quartum  ventriculum  (cerebral  aqueduct). 
Laterally, — the  optic  thalami  and  the  peduncles  of  the  pineal  body. 

The  Optic  Thalami  are  two  large,  oblong  masses,  composed  mainly  of 
gray  matter  and  situated  on  either  side  of  the  3d  ventricle,  between  the 
diverging  portions  of  the  corpora  striata.  Their  outer  and  inferior 
surfaces  are  blended  with  contiguous  parts  of  the  brain;  their  upper,  inner 
and  posterior  surfaces  are  free.  They  are  intimately  connected,  by  com- 
municating fibres,  with  the  tegmenta  of  the  crura  cerebri,  the  optic  tract, 
the  cerebral  cortex,  the  corpora  striata  and  the  corpora  albicantia  (corpora 
mammillaria).  Each  optic  thalamus  terminates  anteriorly  as  a  rounded 
point  — 

Anterior  Tubercle, — containing  the  anterior  nucleus. 

As  they  pass  backwards  the  optic  thalami  diverge  outwards  from 
each  other  and  each  terminates  as  a  rounded  swelling,  the 

Posterior  Tubercle  or  Pulvinar  to  which  is  attached  laterally  the  external 
geniculate  body  (corpus  geniculatum  laterale). 

Corpora  Geniculata  (metathalamus)  four  oval  eminences,  a  pair  of 
which  is  situated  below  and  external  to  the  pulvinar  of  the  thalamus 
on  each  side  of  the  brain. 

External  Geniculate  Body  (corpus  geniculatum  laterale)  the  larger  of  the 


IQ4  HUMAN   ANATOMY 

pair,  is  at  a  higher  level  and  is  slightly  anterior  as  well  as  external 
or  lateral  to  the  internal  geniculate  body  (corpus  geniculatum 
mediale).  The  external  geniculate  body  (corpus  geniculatum 
laterale)  belongs  to  and  is  properly  a  part  of  the  optic  thalamus,  it 
receives  the  outer  or  lateral  limb  of  the  optic  tract. 
Internal  Geniculate  Body  (corpus  geniculatum  mediale)  receives  the 
outer  part  of  the  inner  or  medial  limb  of  the  optic  tract.  These 
fibres  do  not  however  enter  the  eye,  they  originate  in  one  of  the 
inferior  corpora  quadrigemina  (colliculus  inferior)  on  one  side  of  the 
brain,  run  forwards,  cross  by  way  of  the  optic  chiasm,  and  then  run 
backwards  to  the  internal  (lateral)  genicutate  body  and  inferior 
colliculus  of  the  side  opposite  to  that  of  their  origin,  this  constitutes 
what  is  known  as  the  commissure  of  Gudden. 

Pineal  Body  (corpus  pineale),  or  epiphysis   cerebri,   is  a  small  oval, 
reddish  vascular  body  (or  gland),  situated  in  front  of  the  anterior 
corpora    quadrigemina    (colliculi    superiores)    in  the  mid-line,  just 
over  the  opening  of  the  aquaeductus  cerebri  (Sylvius)  into  the  third 
ventricle.     It  derives  its  blood  supply  from  the  velum  interpositum 
(tela  chorioidea  ventriculi  tertii)  to  which  it  is  firmly  attached.     It 
has  two  peduncles  which  run  forwards,  one  on  each  side  of  the  third 
ventricle,  on  the  inner  or  medial  surfaces  of  the  optic  thalami,  to  join 
the  anterior  pillars  of  the  fornix  (columnae  fornicis). 
The  pineal  body,  classed  as  one  of  the  ductless   glands,  is   not   com- 
posed of  nervous  elements  but  consists  of  numerous  follicles  which  are 
lined  by  epithelium.     Some  of  the  follicles  are  filled  with  a  very  viscid 
liquid  containing  many  epithelial  cells  constituting  what  are  known  as 
corpora  amylacea,  some  contain  sabulous  concretions  of  lime,  magnesia, 
and  ammonia  salts  (brain  sand)  constituting  what  is  known  as  the  acervulus 
cerebri.     The  pineal  body  is  homologous  to  the  so-called  "pineal  eye"  of 
some  reptiles  and  some  of  the  other  lower  vertebrates. 

Trigonum  Habenulae,  a  small  triangular  space  with  the  apex  pointing 
forward,  and  its  base  corresponding  to  one  of  the  anterior  corpora 
quadrigemina  (colliculus  superior).  It  is  the  interval  between  one 
of  the  crura  or  peduncles  of  the  pineal  body  and  the  optic  thalamus  of 
the  same  side.  In  this  triangle  is  a  cluster  of  nerve  cells  forming  the 
ganglion  habenulce. 

The  Mesencephalon  or  Mid-brain  is  the  so-called  isthmus  cerebri. 
It  is  the  constricted  portion  which  connects  the  pons  (varolii)  with  the 
diencephalon  (inter-brain  or  thalamen-cephalon)  and  the  cerebral  hemi- 
spheres. Comprised  in  it,  on  its  ventral  surface  are  the  two  crura  (pedun- 


THE   BRAIN  I 95 

culi)  cetebriy  and  on  its  dorsal  surface  are  the  four  corpora  quadrigemina 
(colliculi).  It  is  traversed  by  the  eqtusductus  cerebri  (Sylvius).  Above 
and  in  front,  it  is  continuous  with  the  diencephalon  or  inter-brain,  and 
below  with  the  pons  Varolii. 

The  Crura  Cerebri  (pedunculi  cerebri),  two  thick  conical  stalks 
which  constitute  the  stems  of  the  cerebral  hemispheres,  are  the  upward 
continuation  of  the  medulla  oblongata.  Their  parallel  portions  are 
blended  and  held  together  by  a  mesial  raphe  which  is  indicated  in  front 
or  ventrally  by  a  longitudinal  groove.  This  portion  is  covered  in  front 
or  ventrally  by  the  pons  Varolii.  The  crura  (peduncles)  as  they  emerge 
above  the  upper  border  of  the  pons  Varolii,  diverge  laterally  from 
each  other,  enlarging  as  they  ascend. 

Each  crus  (pedunculus)  then  passes  beneath  the  optic  thalamus  and 
enters  a  cerebral  hemisphere  and  continues  to  the  internal  capsule.  As 
seen  from  in  front  or  ventrally,  the  interval  between  the  divergent  crura 
(pedunculi)  cerebri  is  called  the  inter-peduncular  space. 

In  this  space  are  the  corpora  albicantia  (corpora  mammillaria) . 
The  floor  of  the  space  is  formed  by  the  substantia  perforata  posterior  also 
called  the  posterior  perforated  space.  The  inner  or  medial  sides  of  the 
crura  (pedunculi)  cerebri  are  grooved  by  the  superficial  origin  of  third  or 
oculo-motor  nerves.  Winding  forward  around  the  outer  or  lateral 
sides  of  the  crura  (pedunculi)  cerebri  are  the  optic  tracts  and  below  them, 
the  fourth  or  trochlear  nerves.  On  the  dorsal  surface  of  the  crura 
(pedunculi)  cerebri  are  the  corpora  quadrigemina  (colliculi)  supported 
by  the  lamina  quadrigemina  covering  in  the  aquaeductus  cerebri 
(Sylvius). 

Upon  cross  section,  each  crus  (peduncle)  will  be  found  to  consist  of 
two  portions  which  are  separated  from  each  other  by  a  darker  colored 
portion  called  the  substantia  nigra,  the  portion  that  is  in  front  of  or 
ventral  to  the  substantia  nigra  is  the  Crusta  or  Pes  (Basis  Pedunculi) 
Cerebri;  the  portion  that  is  behind  or  dorsal  to  the  substantia  nigra  is  the 
Tegmentum. 

The  Crusta  (Basis  Pedunculi)  Cerebri  constitutes  the  anterior  or  ventral 
part  of  the  crura  (pedunculi)  cerebri.  It  is  composed  entirely  of  longi- 
tudinal fibres  which  descend  from  the  cerebral  hemisphere  (corticifugal 
fibres)  most  of  which  are  continuous  with  the  pyramidal  tracts  of  the 
medulla.  Three  principal  tracts  or  bundles  are  recognized:  ist,  pyramidal 
tracts  in  the  middle  and  inner  portions  of  the  crusta,  the  inner  part  being 
the  geniculate  fasciculus  and  the  outer  the  pyramidal  tracts  proper;  2df 
cortico-pontine;  and  3d,  caudate-cerebellar  tracts. 


196  HUMAN    ANATOMY 

The  pyramidal  (cerebro-spinal)  tracts  are  direct  motor  strands  com- 
posed of  descending  cortico-spinal  projection  fibres  which  originate  in  the 
following  way.  As  the  axis-cylinder  processes  descend  from  cells  in  the 
precentral  cerebral  cortex,  they  form  the  corona  radiata  by  converging  as 
they  approach  the  internal  capsule.  They  then  proceed  through  the 
genu  and  the  anterior  two-thirds  of  the  posterior  limb  (pars  ocdpitalis}  of 
the  internal  capsule  to  be  continued  as  the  pyramidal  tracts  in  the  crusta 
(basis)  of  the  crus  (pedunculus)  cerebri.  Here  they  are  differentiated 
into  an  inner  and  an  outer  portion. 

The  inner  portion  is  the  part  of  the  pyramidal  tract  that  came  down 
through  the  genu  of  the  internal  capsule,  it  is  continued  as  the  gen- 
iculate  fasciculus,  the  fibres  of  which  terminate  in  the  nuclei  of  the 
5th,  yth,  and  i2th  cranial  nerves. 

The  outer  portion  of  the  pyramidal  tract  is  the  part  that  traversed  the 
anterior  two-thirds  of  the  pars  ocdpitalis  (posterior  limb)  of  the  in- 
ternal capsule,  it  is  continued  as  the, — 

i.  Pyramidal  Tract  Proper  through  the  pons  Varolii  into  the  anterior 
pyramid  (ventral  area)  of  the  medulla  where  its  fibres  are  differenti- 
ated into  three  strands,  the  crossed,  the  direct,  and  the  uncrossed. 
Crossed  Pyramidal  Tract  (fasciculus  cerebro-spinalis  lateralis). 
Most  of  the  fibres  of  the  pyramidal  tract  proper  decussate  in  the 
medulla  (inferior  pyramidal  motor  decussation)  and  are  then  con- 
tinued downwards  as  the  crossed  pyramidal  tract  (lateral  cerebro- 
spinal  fasciculus)  in  the  lateral  column  (funiculus  lateralis)  of  the 
spinal  cord  (medulla  spinalis),  on  the  side  opposite  to  that  of  their 
origin,  to  ultimately  become  connected  with  the  anterior  roots  of 
the  spinal  nerves. 

Direct  Pyramidal  Tract  (fasciculus  cerebro-spinalis  anterior)  or 
fasciculus  of  Tiirck,  is  composed  of  fibres  of  the  pyramidal  tract 
proper  which  do  not  decussate  in  the  medulla  but  continue  downwards 
in  anterior  column  (funiculus  anterior)  of  the  spinal  cord  (medulla 
spinalis),  on  the  same  side  as  that  of  their  origin,  where  at  various 
levels  its  fibres  cross  through  the  gray  matter  of  the  cord  to  become 
connected  with  anterior  nerve  roots  of  the  opposite  side. 
Uncrossed  Pyramidal  Tract  comprises  those  fibres  of  the  pyramidal 
tract  proper  which  do  not  decussate  either  in  the  medulla  or  in  the 
cord  but  continue  downwards  in  the  lateral  column  (funiculus  lateralis) 
of  the  spinal  cord  (medulla  spinalis),  on  the  same  side  as  that  of  their 
origin,  where  they  mingle  with  the  fibres  of  the  crossed  pyramidal 
tract  (fasciculus  cerebro-spinalis  lateralis)  and  become  connected 
with  anterior  nerve  roots  on  the  same  side  as  that  of  their  origin. 


THE   BRAIN  IQ7 

2.  The  Cortico-pontine  Tracts  are  the  first  link  of  the  neurone  chain 
constituting    the    indirect    motor  tract,   the  complete   series  being 
cerebral  cortex;   cortico-pontine   tract;   nucleus  points;   cerebellar 
cortex;  dentate  nucleus;  superior  peduncle  (brachium  conjunctevum) 
of    cerebellum;  red  nucleus    (nucleus    ruber);    rubro-spinal    tract; 
spinal  gray  matter;  spinal  nerve  to  muscle.     There  are  two  groups 
of  cortico-pontine  fibres, — 

Fr  onto- p  online  tract,  during  its  passage  through  the  cerebral  peduncle 
lies  medial  to  the  geniculate  fasciculus  of  the  pyramidal  tract.  Origi- 
nating in  the  mid-frontal  cortex,  its  fibres  pass  through  the  back 
part  of  the  anterior  limb  (pars  frontalis)  of  the  internal  capsule  con- 
tinuing by  way  of  the  crusta  (basis)  pedunculi  cerebri  to  the  nucleus 
pontis. 

Temporo-pontine  tract  which  lies  posterior  and  lateral  to  the  principal 
portion  of  the  pyramidal  tract  during  its  course  through  the  crus 
(pedunculus)  cerebri.  Originating  in  the  cortex  of  the  two  lowermost 
temporal  gyri,  its  fibres  pass  inwards  under  the  lenticular  (lentiform) 
nucleus,  traverse  the  postero-inferior  part  of  the  posterior  limb 
(pars  occipitalis)  of  the  internal  capsule,  continuing  by  way  of 
the  crusta  (basis)  of  the  crus  (pedunculus)  cerebri  to  the  nucleus 
pontis. 

3.  Caudate-cerebellar  Tract  (stratum  intermedium)  occupies  the  interval 
•""between  the  substantia  nigra  which  is  posterior,  and  the  pyramidal 

and  cortico-pontine  tracts  which  surround  it  in  front  and  laterally. 
It  is  made  up  of  fibres  running  from  the  caudate  nucleus  to  the 
cerebellum. 

Substantia  Nigra, — is  a  dark  band  of  pigmented  gray  matter,  semi- 
lunar  in  cross  section.  It  divides  the  basilar  (crusta)  portion  of  the 
cerebral  peduncle  (crus)  from  the  tegmental  portion. 

Tegmentum, — of  the  cerebral  peduncle  (crus)  consists  of  network  of 
transverse  and  longitudinal  fibres  among  which  are  enmeshed  many 
scattered  nerve  cells  and  two  well-defined  clusters  of  nerve  cells. 
The  gray  matter  (substantia  grisea)  of  the  tegmentum  is  continu- 
ous with  the  formatio  reticularis  of  the  pons  and  medulla,  the  prin- 
cipal nuclear  clusters  are, — 

1.  Stratum  Griseum  Cenlrale, — which  is  the  gray  matter  surrounding 
the  aquasductus  cerebri  (Sylvius). 

2.  Red  Nucleus    (nucleus    tegmenti    ruber), — consists  of    multi-polar 
cells,    it   is   situated   beneath  the  anterior  corpus  quadrigeminum 
(colliculus  superior). 

It  is  the  termination  of  the  superior  cerebellar  peduncles   (brachia 


198  HUMAN    ANATOMY 

conjunctiva).  Some  of  the  fibres  originating  in  it  run  up  to  the 
ventro-lateral  nucleus  of  the  thalamus,  others  descend  in  the  rubro- 
spinal  tract. 

While  Matter  (substantia  alba), — of  the  tegmentum  consists  both  of 
transverse  and  longitudinal  fibres.  Its  transverse  fibres  mostly 
enter  into  the  formation  of  oculo-motor  and  trochlear  nerves,  q.  v. 
Its  longitudinal  fibres  are  mostly  sensory  and  ascend  towards  the 
brain  cortex  (corticipital).  They  are  differentiated  into  the  follow- 
ing main  bundles. 

i.  Medial  Lemniscus  (medial  fillet).  The  tegmental  and  pontine 
portion  consists  of  ascending  (corticipital)  sensory  nerve  fibres  after 
they  have  emerged  from  the  superior  pyramidal  sensor.y  decussation 
which  is  just  above  the  nucleus  gracilis  and  nucleus  cuneatus  in  the 
back  part  of  the  medulla  oblongata.  They  convey  sensory  impulses 
from  muscles,  bones,  and  joints.  The  medial  lemniscus  is  formed  by 
the  combination  of  fibres  arising  from  the  nuclei  of  the  fasciculus 
gracilis  and  fasciculus  cuneatus.  They  originate  in  the  following 
way, — The  sense-organs  in  muscles,  bones,  and  joints  are  connected 
by  the  peripheral  processes  (dendrites)  to  the  ganglion  cells  (ist 
neurones  of  the  chain)  in  the  ganglia  on  the  posterior  roots  of  the  spinal 
nerves,  by  way  of  which,  the  central  processes  (axones)  of  those  cells 
enter  and  then  run  upwards  in  the  posterior  column  (funiculus 
posterior)  of  the  spinal  cord  (medulla  spinalis)  on  the  same  side  as 
that  of  their  origin.  All  those  coming  from  spinal  nerves  below  the 
8th  thoracic,  are  combined  to  form  the  Fasciculus  Gracilis  (column 
of  Goll)  occupying  the  medial  portion  of  the  posterior  column  (funicu- 
lus posterior)  of  the  cord,  in  which  position  it  continues  as  it  runs 
upwards  to  the  medulla  where  it  terminates  in  an  expansion  enclosing 
the  nucleus  gracilis,  this  upper  portion  being  known  as  the  clava. 
The  Fasciculus  Cuneatus  (column  of  Burdach)  originates  in  exactly 
the  same  way  from  all  of  the  spinal  nerves  above  the  Qth  thoracic. 
It  runs  upwards,  laterally  to  the  fasciculus  gracilis,  in  the  posterior 
column  (funiculus  posterior)  of  the  cord  until  it  reaches  the  medulla 
in  which  it  terminates  as  an  expansion  enclosing  the  nucleus  cuneatus. 
The  2d  neurones  of  the  chain  after  leaving  the  nucleus  gracilis  or 
nucleus  cuneatus,  may  go  by  way  of  the  inferior  cerebellar  peduncle 
(corpus  restifcrme)  to  the  cerebellar  cortex  of  the  opposite  side,  or 
they  may  decussate  in  the  medulla  (superior  Pyramidal  sensory 
decussation)  and  then  proceed  as  medial  lemniscus  or  fillet  by  way  of 
the  pons  through  the  tegmentum  of  the  crus  (pediculus)  cerebri  of 
the  side  opposite  to  that  of  their  origin;  then  through  the  thalamus, 


THE  BRAIN  1 99 

or  through  the  posterior  limb  (pars  occipitalis)  of  the  internal  capsule, 
to  the  cerebral  cortex. 

2.  Lateral  Lemniscus    (lateral   fillet),  is  the   upward  continuation  of 
the  cochlear  division  of  the  central  auditory  tract.     Its  fibres  are 
derived  in  the  following  way, — The  cochlear  nerve  arises  from  the  cen- 
tral processes  of  the  T-shaped  cells  (ist  neurone  of  the  chain)  in  the 
spiral   ganglion    of    the    cochlea,    it    then    passes   backwards    and 
enters  the   medulla,   beneath  the   lower  border    of    the    pons   on 
the  outer  side  of  the  restiform  body.     Its  fibres  then  divide  into 
ascending  and  descending  branches.     The  fibres  of  the  ascending 
branch  terminate  in  the  cells  of  the  ventral  cochlear  nucleus,  which 
lies  in  front  of  the  restiform  body  in  the  interval  between  the  cochlear 
and  vestibular  divisions  of  the  auditory  nerve  (n.  acusticus).     The 
fibres  of  the  descending  branch  terminate  in  the  cells  of  the  dorsal 
cochlear  nucleus,  which  lies  beneath  the  trigonum  acusticum,  behind 
the  restiform  body  and  between  it  and  the  flocculus  of  the  cerebellum. 
The  axones  of  the  cells   (2d  neurone)   in  the  dorsal  and  ventral 
cochlear  nuclei  form  two  bundles,  of  which  the  dorsal  bundle  or  striae 
medullares  cross  the  floor  of  the  4th  ventricle  to  the  medial  plane  in 
which   they  penetrate  the  tegmentum  and  decussate,  some  of  the 
fibres  entering  the  lateral  lemniscus  of  the  opposite  side,  others  enter- 
ing the  trapezoid  body  (corpus  trapezoideum). 

The  axones  in  the  ventral  bundle  (trapezia!)  enter  the  trapezoid  body 
where  some  of  them  terminate  in  the  large  cells  (3d  neurone)  constituting 
the  nucleus  trapezoideus.  Most  of  these  trapezial  axones  decussate  before 
terminating  in  the  superior  olive.  The  axones  leaving  the  superior  olive 
(4th  neurone)  are  joined  by  the  axones  of  the  dorsal  bundle  (strife  medul- 
lares) so  constituting  the  lateral  lemniscus  (lateral  fillet)  which  bends 
upwards  and  is  again  interrupted  by  the  nucleus  lemnisci  lateralis  (5th 
neurone)  whence  it  proceeds  by  way  of  the  tegmentum  to  the  nucleus  of 
the  posterior  quadrigeminal  body  (colliculus  inferior)  (6th  neurone)  and 
to  the  medial  geniculate  body  (;th  neurone)  from  which  arise  axones  that 
pass  through  the  sub-lenticular  portion  of  the  internal  capsule,  then  by  way 
of  the  temporal  portion  of  the  corona  radiata  to  the  auditory  area  in  the 
cortex  of  the  superior  and  transverse  temporal  gyri.  A  few  fibres  reach  the 
posterior  corpora  quadrigemina  (colliculi  inferiores)  without  having 
decussated. 

3.  Ventral    Longitudinal    Fasciculus    (tecto-spinal    or    mesencephalo- 
spinal  tract,  or  sulco-marginal  fasciculus), — is  composed  of  axones 
descending  from  the  anterior  corpora  quadrigemina  (colliculi  supe- 
riores).     These  fibres  immediately  commence  to  decussate  (  optic 


200  HUMAN   ANATOMY 

acoustic  reflex  path")  and  as  they  descend,  continue  to  decussate 
through  the  medial  raphe  on  each  side  of  which  they  lie.  During  the 
course  of  this  tract  through  the  pons  and  medulla  many  of  its  fibres 
terminate  in  the  nuclei  of  all  of  the  motor  cranial  nerves,  the  tract  it- 
self enters  the  anterior  column  (funiculus  anterior  medullas  spinalis) 
of  the  cord  on  the  side  opposite  to  that  of  its  origin.  Continuing  down- 
wards, between  the  direct  pyramidal  tract  (ventral  cerebro-spinal 
fasciculus)  and  the  anterior  medial  fissure,  its  fibres  terminate  in 
cells  of  the  anterior  horn  (columna  anterior). 

4.  Medial  Longitudinal  Fasciculus  (posterior  longitudinal  bundle), — is 
composed  mostly  of  short  association  fibres.     It  originates  in  a  special 
nucleus  of  its  own  that  is  situated  in  that  part  of  the  floor  of  the  3d 
ventricle  which  is  immediately  behind,  or  above,  the  corpora  albicantia 
(corpora  mammillaria);  it  passes  downwards,  close  to  the  mid-line, 
between  the  medial  lemniscus  (medial  fillet)  and  the  gray  matter 
(substantia  griesea  centralis)  of  the  aquaeductus  cerebri  (Sylvius), 
where  it  becomes  intimately  connected  with  the  nuclei  of  the  3d, 
4th,  and  6th  cranial  nerves,  and  the  cells  of  the  anterior  corpus  quad- 
rigeminum  (colliculus  superior)      It  continues  downwards  close  to  the 
mid-line  immediately  in  front  of  the  gray  matter  forming  the  floor  of 
the  4th  ventricle  where  it  becomes  connected  with  the  nuclei  of  the 
7th  and  vestibular  portion  of  the  8th  cranial  nerves.     It  gives  off 
and  receives  many  collaterals  in  the  formatio  (substantia)  reticularis 
as  it  traverses  the  pons  and  medulla  in  order  to  enter  the  anterior 
column  (funiculus  anterior  medullae  spinalis)  of  the  cord  where  its 
fibres  terminate  in  the  cells  of  the  anterior  horn  (columnae  anterior). 
This  tract  seems  to  be  made  up  mostly  of  fibres  which  have  decussated. 
Throughout  its  entire  course  it  always  lies  close  to  the  mid-line 
immediately  in  front  of  the  central  gray  matter,  of  whatever  structure 
it  traverses. 

5.  Spino-thalamic  Tract, — is  composed  of  direct  ascending  fibres  which 
transmit  sensation  of  pain,  heat  and  cold,  pressure  and  touch,  from  the 
skin  on  one  side  of  the  body  to  the  opposite  side  of  the  brain.     The 
sensory  end-organs  of  the  skin  are  connected  with  the  peripheral 
processes  (dendrites)  of  cells  in  the  ganglia  of  the  posterior  roots  of 
the  spinal  nerves.     The  central  processes  (axones)  of  these  cells  are 
connected  with  cells  in  the  gray  matter  of  the  posterior  horn  (columna 
posterior)  of  the  cord  (medulla  spinalis)  from  which  axones  pass 
forwards  and  cross  by  way  of  the  anterior  white  commissure  to  the 
opposite  side  of  the  cord  (medulla  spinalis)  where  they  ascend,  at 
first  loosely  scattered,  in  the  antero-lateral  funiculus,  they  ultimately 


THE  BRAIN  2OI 

become  condensed  into  a  distinct  tract  or  fasciculus  which  ascends 
in  the  lateral  side  of  the  medulla,  continues  upwards  through  the  pons, 
medial  to  the  olivo-cerebellar  and  rubro-spinal  tracts,  then,  along 
with  the  medial  lemniscus,  it  traverses  the  tegmentum  and  the 
posterior  limb  (pars  occipitalis)  of  the  internal  capsule  to  terminate 
in  the  thalamus. 

6.  Superior  Peduncles  (brachia  conjunctiva)  of  the  Cerebellum, — consists 
of  fibres  originating  in  the  dentate  nuclei  of  the  cerebellum.     They 
are  two  white  bands,  a  right  and  a  left,  which  emerge,  widely  apart, 
from  the  front  of  the  cerebellum.     As  they  run  upwards  and  for- 
wards they  converge  forming  the  lateral  boundaries  and  a  small  por- 
tion of  the  roof  of  the  front  or  upper  half  of  the  4th  ventricle.    They 
join  each  other  in  the  mid-line,  decussate  and  then  pass  upwards 
under  cover  of  the  posterior  pair  of  corpora  quadrigemina  (colliculi 
inferiores)  each  one  terminating  in  the  red  nucleus  (nucleus  tegmenti 
ruber)  of  the  side  opposite  to  that  of  its  origin. 

7.  Rubro-spinal    tract     (pre-pyramidal    or    Monakow's    tract), — is    a 
descending  crossed  motor  strand  which  seems  to  be  the  downward 
continuation  of  some  of  the  fibres  of  the  superior  peduncles  (brachia 
conjunctiva)  of  the  cerebellum  which  having  come  from  the  dentate 
nucleus  and  crossed  to  the  red  nucleus  of  the  opposite  side,  are  by 
means  of  the  rubro-spinal  tract  connected  to  their  original  side  of  the 
spinal  cord.     The  fibres  of  the  rubro-spinal  tract  originate  in  the  red 
nucleus  (nucleus  tegmenti  ruber)  just  beneath  the  anterior  corpus 
quadrigeminum  (colliculus  superior)  they  cross  the  medial  plane  to 
the  opposite  side,  descend  close  to  the  lateral  lemniscus  behind  the 
trapezium  in  the  pons,  becoming  superficial  in  the  medulla,  where 
they  lie  in  the  furrow  of  the  lateral  area  or  pyramid  between  the  olive 
and  the  spinal  tract  of  the  trigeminal  nerve,  they  enter  the  lateral 
column  (funiculus  lateralis)   of  the  spinal  cord  (medulla  spinalis) 
where  they  continue  downwards  immediately  in  front  of  the  crossed 
pyramidal  tract  (fasciculus  cerebro-spinalis  lateralis)   which  is  in- 
vaded by  some  of  the  fibres,  the  others  terminating  in  the  cells  of  the 
anterior  horn  (columna  anterior). 

8.  Descending   (Mesencephalic)   Root  of  the   Trigeminal  Nerve, — enters 
into  the  composition  of  the  Masticator  Nerve  (motor  portion  of  the 
fifth).     Its  fibres  originate  in  the  giant  pyramidal  cells  in  the  lower 
part  of  the  somaesthetic  (sensory-motor)  area  of  the  cerebral  cortex. 
These  pyramidal  fibres  traverse  the  genu  of  the  internal  capsule, 
continue  through  the  tegmentum,  medial  to  the  superior  peduncle 
(brachium  conjunctivum)  of  the  cerebellum,  then  decussate  before 


202  HUMAN    ANATOMY 

terminating  in  accessory  motor  nucleus  of  the  fifth  nerve.  This 
nucleus  is  also  known  as  the  Mesencephalic  Nucleus  of  the  Masticator 
Nerve,  it  is  a  column  of  gray  matter  lateral  to  the  gray  matter  (stra- 
tum griseum  centrale)  surrounding  the  cerebral  aqueduct  (Sylvius). 
9.  Olivary  Fasciculus  (thalamo-olivary  or  central  tegmental  tract), — 
is  composed  of  fibres  that  originate  both  in  the  lenticular  (lentiform) 
nucleus  and  the  thalamus,  traverse  the  central  portion  of  the  tegmen- 
tum  and  continue  in  the  pons,  behind  the  medial  lemniscus  in  the 
formatio  reticularis  to  the  inferior  olivary  nucleus,  being  continued 
from  the  olive  to  the  opposite  cerebellar  hemisphere  by  way  of  the 
cerebello-olivary  fibres. 

Corpora  Quadrigemina  (colliculi)  are  4  rounded  eminences  placed  in 
pairs,  2  in  front  and  2  behind,  on  the  dorsal  surface  of  the  mid-brain 
(mesencephalon)  immediately  behind  the  3d  ventricle  and  beneath  the 
posterior  border  of  the  corpus  callosum.  All  4  collectively  are  often  called 
the  Tectum  or  Tectum  Mesencephali,  e.g.,  in  names  such  as  uteclo-spinal.n 
The  upper  or  anterior  pair  were  called  the  nates  (colliculi  superiores),  the 
lower  pair  the  lestes  (colliculi  inferiores).  They  are  connected  by  4  bands, 
the  brachia,  with  the  corpora  geniculata,  those  of  the  anterior  corpora 
quadrigemina  (colliculi  superiores)  being  continued  directly  into  the  optic 
tract.  They  are  composed  of  white  matter  externally  and  gray  matter 
internally.  The  anterior  pair  contain  the — 

Stratum  Zonale, — a  thin  stratum  of  white  matter  on  the  surface. 

Stratum  Cinereum  (stratum  griseum  colliculi  superioris), — next  below, 
a  layer  of  gray  matter. 

Stratum  Opticum, — the  upper  gray- white  layer,  having  many  fine  nerve- 
fibres  intersecting  the  gray  matter. 

Stratum  Lemnisci, — the  deep  gray-white  layer,  consisting  of  nerve- 
fibres  and  nerve-cells  of  large  size. 

Aqueduct  of  Sylvius,  or  Her  a  tertio  ad  quartum  ventriculum  (aquaeductus 
cerebri)  is  a  narrow  canal,  about  ^  inch  long,  connecting  the  3d  ventricle 
with  the  4th,  and  situated  between  the  corpora  quadrigemina  (colliculi) 
and  the  tegmentum.  It  is  surrounded  by  a  layer  of  gray  matter  (stratum 
griseum  centrale)  which  is  continuous  with  the  gray  matter  of  the  3d  and 
4th  ventricles,  and  contains  groups  of  cells  which  are  connected  with  the 
roots  of  the  3d,  4th  and  5th  cranial  nerves. 

The  Hypo-thalamic  Region  (right  or  left), — is  the  forward  prolongation 
of  the  tegmentum  becoming  blended  with  the  under  surface  of  the  thala- 
mus, it  consists  mainly  of  the  upward  and  forward  production  of  the  red 
nucleus  (nucleus  tegmenti  ruber),  medial  lemniscus  (fillet),  and  the  sub- 


THE  BRAIN 


203 


stantia  nigra  which  is  here  expanded  laterally  by  an  additional  cluster  of 
nerve  cells  forming  the  Nucleus  Hypothalamicus. 

The  Rhombencephalon  morphologically  comprises:  i.  isthmus  rhom- 
bencephali,  2.  metencephalon,  and  3.  myelencephalon. 

Isthmus  Rhomb encephali  (isthmus  of  the  hind-brain)  comprises: 

a.  Superior  Peduncles  (brachia  conjunctiva)   of  the  cerebellum  (see 

page  201). 

b.  Superior  Medullary  Velum  (valve  of  Vieussens)  is  triangular  in  shape 

with  the  apex  pointing  forwards.  It  forms  the  roof  of  the  anterior 
or  upper  half  of  the  4th  ventricle  by  filling  up  the  interval  between 
the  two  superior  peduncles  (brachia  conjunctiva)  of  the  cerebellum. 
It  consists  of  a  lamina  of  white  matter  which  is  crossed  on  its  upper 
surface  by  several  transverse  bands  of  gray  matter  which  collec- 
tively are  known  as  the  lingula  cerebelli. 

The  Metencephalon  or  the  Hind-brain,  — comprises  the  pons  Varolii, 
the  Cerebellum,  and  the  upper  half  of  the  4th  Ventricle.  The  latter  is 
described  with  its  lower  half,  under  the  Medulla  Oblongata,  in  the  next 
section. 

FIG.  73. 


13 


17 


The  Pons  Varolii  (6),  is  the  bond  of  union  of  the  various  parts  of  the 
brain,  connecting  the  cerebrum  with  the  cerebellum  (3)  and  the  medulla 
oblongata  (9).  It  is  about  i^  inch  wide  and  i  inch  long  and  thick,  and  is 
situated  between,  the  hemispheres  of  the  cerebellum  above  the  medulla 
oblongata  and  below  the  crura  (pedunculi)  cerebri.  It  consists  of — a 
ventral  or  anterior  portion  (pars  ventralis)  (7),  containing  layers  of  trans- 


•) 

4 

jj 

4 


2CH  HUMAN    ANATOMY 

verse  and  longitudinal  fibres,  also  a  small  quantity  of  gray  matter,  a 
tegmental,  dorsal,  or  posterior  portion  (pars  dorsalis),  which  is  a  continua- 
tion of  the  reticular  formation  of  the  medulla,  most  of  its  constituents 
being  continued  into  the  tegmentum  of  the  crura  (pedunculi)  cerebri. 

The  Gray  Matter  of  the  Pons  consists  of  the  following  important 
collections  of  nerve-cells: — 

Superior  Olivary  Nucleus  (nucleus  olivarius  superior), — an  isolated  mass 

of  gray  matter  situated  on  the  dorsal  surface  immediately  above  the 

inferior  olivary  nucleus  (nucleus  olivarius  inferior)  of  the  medulla. 
Nuclei  of  the  $th  Nerve  2, — one  for  the  motor  (12)  and  one  for  the  sensory 

root  (13),  the  latter  external  to  the  former. 
Nucleus  of  the  6th  Nerve, — beneath  the  floor  of  the  4th  ventricle,  close 

to  the  root  of  the  facial  nerve;  its  fibres  pass  through  the  pons  and 

emerge  at  its  lower  margin  (14). 
Nucleus  of  the  Facial  (jth)  Nerve, — situated  deeply  below  the  floor  of  the 

4th  ventricle;  its  roots  follow  a  tortuous  course  in  the  pons,  emerging 

at  its  lower  border  (15),  external  to  those  of  the  abducent  nerve. 
Nuclei  of  the  Auditory  (Sth)  Nerve  2, — are  dorsal  and  ventral,  both  lying 

chiefly  in  the  medulla  but  prolonged  into  the  pons;  the  roots  emerging 

at  its  lower  border  (17),  in  the  groove  between  the  olivary  body  (oliva) 

and  the  restiform  body  (corpus  restiforme). 
Nuclei  Pontis, — small  masses  of  gray  matter  in  the  ventral  or  anterior 

portion  of  the  pons. 
Substantia  Gelalinosa  (of  Rolando), — which  is  continuous  with  that  of 

the  spinal  cord  and  medulla. 
Locus  Cceruleus,  a  slate-colored  bluish  spot  on  the  upper  part  of  the 

floor  of  the  4th  ventricle. 

The  White  Matter  of  the  Pons  consists  of  4  sets  of  medullated  nerve 
fibres,  superficial  transverse,  superficial  longitudinal,  deep  transverse  and 
deep  longitudinal. 

The  Superficial  Transverse  Fibres, — are  on  the  ventral  surface  of  the 
pons,  they  continue  laterally  into  the  middle  peduncles   (brachia 
pontis)  of  the  cerebellum. 
The  Superficial  Longitudinal  Fibres  of  the  pons  comprise, — • 

1.  Upward  continuation  of  the  anterior  pyramids  (ventral  area)  of 
the  medulla  (see  page  209). 

2.  Cortico-pontine  Tracts  (see  page  197). 

3.  Stratum  Intermedium  or  Caudate-cerebellar  Tract  (see  page  197). 
The  Deep  Transverse  Fibres, — form  the  trapezium  (corpus  trapezoideum) 

and  then  pass  laterally  into  the  middle  peduncles  (brachia  pontis) 


THE  BRAIN  205 

of  the  cerebellum  (see  lateral  lemniscus,  page  199,  and  acoustic  nerve, 
page  220). 

The  Deep  Longitudinal  Fibres, — of  the  pons  constitute  a  portion  of  the 
reticular  formation  in  which  the  following  distinct  bundles  can  be 
traced, — 

1.  Olivary  Fasciculus,  Thalamo-olivary  or  Central  Tegmental  Tract 
(see  page  202),  lies  in  the  reticular  formation  dorsal  to  the  medial 
lemniscus. 

2.  Descending  or  Mesencephalic  Root  of  the  Trigeminal  Nerve  (see 
page  201). 

3.  Fasciculus  Teres,  is  composed  of  fibres  of  the  facial  nerve  which,  by 
looping  upwards  behind  the  nucleus  of  the  abducens  nerve  and  then 
running  forwards  and  upwards,  forms  the  eminentia  teres  or  medialis 
(colliculus  facialis)  which  lies  in  the  floor  of  the  anterior  or  upper 
half  of  the  4th  ventricle,  immediately  lateral  to  the  mid-line. 

4.  Medial  Lemniscus  or  Fillet  (see  page  198),  which  comprises  the 
fasciculus  gracilis  (column  of  Goll)   and  the  fasciculus  cuneatus 
(column  of  Burdach). 

5.  Lateral  Lemniscus  or  Fillet  (see  page  199),  composed  of  the  cochlear 
fibres  of  the  central  auditory  path. 

6.  Ventral  Longitudinal  or  Sulco-marginal  Fasciculus  (Tecto-spinal 
or  Mesencephalo-spinal  Tract)  (see  page  199). 

7.  Medial  Longitudinal   Fasciculus   (Posterior  Longitudinal  Tract) 
(see  page  200). 

8.  Rubro-spinal  Fasciculus  (Pre-pyramidal  or  Monakow's  Tract)  (see 
page  201). 

9.  Ascending  Antero-lateral   Tract  of    Cowers,  comprises  a  direct 
and  an  indirect  path  through  which  sensation  of  pain,  temperature, 
pressure,  and  touch  reaches  the  brain. 

a.  Spino-thalamic  Tract  is  the  direct  path  (see  page  200). 

b.  Ventral     Spino-cerebellar     Tract     (Superficial     Ventro-lateral 
Spino-cerebellar  Fasciculus)   is  the  indirect  path.     The   term 
"Cowers'  Tract"  is  limited  by  some  to  this  tract  only.     It 
originates  in  the  following  way,  the  sensory  end  organs  are  con- 
nected with  the  peripheral  processes  (dendrites)  of  cells  in  the 
ganglia  of  the  posterior  roots  of  spinal  nerves,  the  central  proc- 
esses   (axones)    of  these  cells  are  connected  with  cells  in  the 
base  of  the  lateral  horn  (columna  lateralis),  known  as"Stillings' 
Nucleus,"  and  with  cells  in  the  lateral  horn  (columna  lateralis) 
of  the  spinal  cord  (medulla  spinalis).     The  axones  of  these  cells, 
both  of  the  same  and  the  opposite  side,  are   agminated  into  a 


206  HUMAN    ANATOMY 

bundle,  the  Ventral  Spino-cerebellar  Tract  (Superficial  Ventro- 
lateral  Spino-cerebellar  Fasciculus)  which  travels  upwards  in  the 
lateral  column  (funiculus  lateralis)  of  the  spinal  cord  (medulla 
spinalis).  It  maintains  this  position  as  it  traverses  the  medulla 
until  it  reaches  the  pons  where  it  runs  forwards  and  upwards  as 
high  as  the  level  of  the  trigeminal  nerve,  it  then  runs  backwards 
and  downwards,  enters  the  superior  peduncle  (brachium  conjunc- 
tivum)  of  the  cerebellum,  and  terminates  in  the  lingula  of  the 
superior  vermis  cerebelli  of  its  own  side. 

The  Cerebellum  consists  of  gray  matter  (substantia  corticalis)  on  the 
surface  and  white  matter  (corpus  medullare)  in  the  interior.     Its  surface 
is  not  convoluted  like  that  of  the  cerebrum,  but  is  traversed  by  curved 
fissures  and  furrows  (sulci),  the  latter  separating  the  laminae  (folia  or  gyri) 
of  which  it  is  composed.     It  lies  in  the  inferior  occipital  fossae  of  the  skull, 
beneath  the  occipital  lobes  of  the  cerebrum,  from  which  it  is  separated  by 
a  process  of  dura  mater,  the  tentorium  cerebelli.     It  is  divided  into  a  cen- 
tral portion  or  lobe,  the  Vermis  Cerebelli  or  Vermiform  Process  (i),  and  two 
lateral  Hemispheres;  all  continuous  with  each  other  and-  substantially  the 
same  in  structure.     It  presents  the  following  primary  fissures: — 
Great  Horizontal  Fissure  (10), — horizontally  round  the  free    margin, 
from  the  pons  in  front  to  the  median  line  behind,  giving  origin  to  the 
secondary  fissures. 
Incisura  Cerebelli  Anterior,  or  Anterior  Cerebellar  Notch, — a  broad, 

shallow,  vertical  notch,  separating  the  hemispheres  in  front. 
Incisura  Marsupialis  (2),  or  Posterior  Cerebellar  Notch, — a  deep  notch, 

separating  the  hemispheres  from  each  other  behind. 
Vallecula, — a  deep  depression  on  the  inferior  surface,  containing  the 

lower  extremity  of  the  vermis  (vermis  inferior). 

Secondary  Fissures  of  the  Cerebellum  are  8  in  number,  4  superiorly  and 
4  inferiorly.     They  pass  in  a  curved  direction  from  side  to  side  across  the 
cerebellum,  beginning  (except  one)  and  ending  in  the  great  horizontal 
fissure.     They  are  named  from  before  backward  as  follows: 
On  the  upper  surface  of  the  cerebellum,  the — 

Pre-central.        Post-central.        Anterior  Semilunar  or  Pre-clival. 

Posterior  Semilunar  or  Post-clival. 
On  the  lower  surface  of  the  cerebellum,  the — 

Post-nodular.  Retro-tons illar  or  Pre- pyramidal. 

Anterior  Inferior  or  Post-pyramidal.    Posterior  Inferior  or  Post-gracile. 
The  post-gracile  is  a  branch  of  the  post-pyramidal,  and  ends  in  the 
great  horizontal  fissure. 


THE   BRAIN  207 

Lobes  of  the  Cerebellum.  The  3  primary  lobes,  the  Vermis  or  Worm 
and  the  Hemispheres,  are  divided  by  the  above-named  secondary  fissures 
into  19  lobes,  named  as  follows: — 

On  the  upper  surface  of  the  Worm  (vermis  superior),  from  before 
backward  5,  the — 

Lingula.  Lobulus  Centralis.  Culmen  Monticuli. 

Diclive  or  Clivus  Monticuli.    Folium  Cacuminis  or  Commissura  Simplex. 
On  the  upper  surface  of  the  Hemispheres,  from  before  backward  5,  the — 
Vinculum  Lingualce  or  Freenulum.  Ala  Lobuli  Centralis. 

A  nterior  Semilimar  or  Crescentic  Lobe.  Posterior  Semihmar  or 

Crescentic  Lobe. 

Superior  Semilunar  or  Posterior  Superior  Lobe. 
On  the  lower  surface  of  the  Worm,  from  before  backward  4,  the — 

Nodule.  Uvula.  Pyramid.  Tuber  Valvula. 

On  the  lower  surface  of  the  Hemispheres,  from  within  outward  5,  the — • 
Flocculus  (5).         Tonsil  or  Amygdala  (4).         Biventral  Lobe  (3). 
Cradle  or  Slender  Lobe  (3).          Inferior  Semilunar  Lobe  (3). 

White  Matter  (Corpus  Medullare)  of  the  Cerebellum  includes  the 
peduncular  fibres  and  the  fibres  proper.  The  former  are  projection  fibres 
and  are  arranged  in  3  peduncles  on  each  side,  which  arise  from  the  anterior 
part  of  the  hemispheres,  and  connect  the  cerebellum  with  itself  and  with 
the  rest  of  the  brain,  as  follows: — 

Superior  Peduncles  (brachia  conjunctiva), — in  part  form  the  roof  of 
the  4th  ventricle;  they  pass  from  the  corpus  dentatum  under  the 
corpora  quadrigemina,  below  which  their  fibres  decussate,  going  to 
the  red  nucleus  of  the  tegmentum,  and  by  a  relay  through  the  optic 
thalamus  to  the  cerebral  cortex.  Stretching  from  one  peduncle  to 
the  other  is  the — 

Valve  of  Vieussens,  or  Superior  Medullary  Velum  (see  page  203), — a 

thin  lamina  of  white  matter,  which  with  the  superior  peduncles  forms 

part  of  the  roof  of  the  4th  ventricle  (see  page  211). 

Middle  Peduncles  (brachia  pontis)  (8), — comprise  most  of  the  transverse 

fibres  of  the  pons,  and  are  chiefly  commissural  fibres  connecting  the 

cerebellar  hemispheres  with  each  other.     All  are  connected  with  the 

nucleus  pontis  of  the  same  or  the  opposite  side,  those  that  are  not 

commissural  are  the  continuation  of  the  cortico-pontine  tracts  (see 

page  197). 

Inferior   Peduncles     (corpora    restiformes), — connect    the    cerebellum 

with  the  medulla  oblongata. 
Fibra  Proprice,  the  proper  fibres  of  the  cerebellum, — are  of  2  kinds;  the 


208  HUMAN    ANATOMY 

commissural,   connecting   the  hemispheres,   and   the  association   or 
arcuate  fibres,  connecting  adjacent  laminae. 

Cortical  Gray  Matter  (Substantia  Corticalis)  of  the  Cerebellum  is 
situated  on  the  surface,  forming  the  cortex,  a  section  of  which  presents  a 
characteristic  foliated  appearance,  named  the  Arbor  Vita,  due  to  the 
branching  of  the  laminae  given  off  from  the  central  white  matter  to  the 
cortical  portion.  The  gray  matter  of  the  cortex  consists  of  three  layers, 
as  follows: 

Molecular  or  External  Gray  Layer, — consists  of  fibres  and  cells. 
Middle  Layer  Containing  the  Cells  of  Purkinje,  (the  characteristic  cells 
of  the  cerebellum),  an  incomplete  stratum  of  flask-shaped  cells,  their 
bases  resting  on  the  granular  layer,  their  necks  giving  off  numerous 
dendrites  to  the  molecular  layer. 

Granular  or  Internal  rust-colored  Layer  of  Turner, — contains  numerous 
small  nerve-cells  or  granules  of  reddish-brown  color,  also  many  nerve- 
fibrils,  among  which  are  the  axones  of  the  Purkinje  cells.  This  layer 
also  contains  larger  cells,  known  as  the  Golgi  cells,  situated  in  its  outer 
part. 

Central  Gray  Matter  of  the  Cerebellum  is  disposed  on  each  side  in  4 
centres,  one  of  which,  the  dentate  nucleus  is  large;  the  others  being  of  small 
size.  They  are  situated  in  the  middle  of  the  white  matter  of  the  organ,  and 
are  as  follows:  the — 

Dentate  Nucleus,  or  Ganglion  of  the  Cerebellum, — an  irregularly  folded 
lamina  of  gray  matter,  having  an  opening  anteriorly,  the  hilum,  from 
which  emerge  most  of  the  fibres  of  the  superior  peduncle  (brachium 
conjunct!  vum.) 

Nucleus  Emboliformis, — lies  to  the  inner  side  of  the  dentate  nucleus, 
partly  covering  its  hilum.     It  is  probably  part  of  the  dentate  nucleus. 
Nucleus  Globosus, — an  elongated  mass  on  the  inner  side  of  the  preceding. 
Nucleus  Fastigii,  or  Roof  Nucleus  of  Stilling, — is  close  to  the  middle  line 
at  the  anterior  end  of  the  vermiform  process  (vermis)  and  imme- 
diately over  the  roof  of  the  4th  ventricle.     The  fibres  of  the  ves- 
tibular  nerve  terminate  in  this  nucleus  after  having  decussated  in  the 
vermis. 

THE  MEDULLA  OBLONGATA 

The  Medulla  Oblongata,  or  Myelencephalon,  formerly  called  the  Spinal 
Bulb,  is  thelowermost  division  of  the  brain  and  is  continuous  with  the  spinal 
cord.  It  extends  from  the  lower  margin  of  the  pons  Varolii  (5)  to  the 
inferior  pyramidal  (motor)  decussation  (12)  corresponding  to  the  lower  mar- 
gin of  the  foramen  magnum.  Its  ventral  surface  rests  on  the  basilar 


THE   BRAIN  209 

groove  of  the  occipital  bone,  its  dorsal  surface  is  in  the  fossa  between  the 
cerebellar  hemispheres.  It  is  i  inch  long,  %  inch  broad  above,  and  ^  inch 
thick;  and  of  pyramidal  form,  its  broad  end  upward.  On  its  surface  are 
the  anterior  and  posterior  median  fissures;  the  former  terminating  just 
below  the  pons  in  a  cul-de-sac,  the  foramen  ccecum;  the  latter  expanding 
into  the  4th  ventricle  about  the  middle  of  the  medulla.  On  each  side  the 
medulla  presents  the  following  parts: — 

Pyramid  (7), — a  bundle  of  white  matter  alongside  the  anterior  median 
fissure,  formed  by  the  upward  continuation  of  the  direct  tract  (fas- 
ciculus cerebro-spinalis  anterior)  of  the  anterior  column  (funiculus 
anterior)  and  the  crossed  tract  (fasciculus  cerebro-spinalis  lateralis) 
of  the  lateral  column  (funiculus  lateralis)  of  the  spinal  cord.  As  the 
latter  tract  ascends  it  decussates  with  its  fellow  of  the  opposite  side 
across  the  fissure,  forming  the  inferior  decussalion  of  the  pyramids 
(8).  Each  pyramid  is  bounded  by  the  antero-lateral  sulcus  which  is 
continuous  with  that  of  the  cord. 

Olive  (Olivary  Body)  (9), — an  ovoid  projection  on  the  outer  side  of  the 
pyramid  and  immediately  below  the  pons.  In  the  groove  between  the 
olive  and  pyramid,  the  hypoglossal  nerve  fibres  (27)  emerge;  in  that 
between  the  olive  and  restiform  body  (inferior  cerebellar  peduncle) 
emerge  the  glosso-pharyngeal 
(24),  pneumogastric  (n.  vagus) 
(25)  and  spinal  accessory  (n. 
accessorius)  (26)  nerves.  The 
Inferior  Olivary  Nucleus  or  corpus 
denlatum  is  a  thin,  wavy  lamina 
of  gray  matter,  open  at  its  upper 
and  inner  part.  Three  accessory 
nuclei  (dorsal,  medial  and 
lateral)  are  also  situated  in  the 
olive. 

Fasciculus  of  Rolando  (10), — a 
slight,  longitudinal  prominence 
on  the  outer  side  of  the  olivary 
body.  It  corresponds  to  a  mass 

of  gray  matter,  substanlia  gelatinosa,  continuous  with  the  posterior 
horn  of  the  gray  matter  of  the  cord. 

Lateral  Column, — hidden  above  by  the  olivary  body  but  showing  below 
it;  is  the  continuation  of  the  lateral  column  (funiculus  lateralis)  of 
the  cord  in  part. 

Restiform    Body    (inferior   cerebellar   peduncle), — between    the  lateral 
14 


210  HUMAN    ANATOMY 

column  and  the  fasciculus  cuneatus;  contains  the  arcuate  fibres, 
external  and  internal,  and  the  dorsal  spino-csr  Cellar  fasciculus  (direct 
cerebellar  tract).  The  two  restiform  bodies  diverge  as  they  ascend, 
assist  in  forming  the  lateral  walls  of  the  4th  ventricle,  and  enter  the 
cerebellar  hemispheres  as  the  inferior  peduncles  of  the  cerebellum. 

Dorsal  S pino-cerebellar  Fasciculus  (direct  cerebellar  tract  of  Flechsig), 
— arises  from  cells  in  the  dorsal  nucleus  (Clark's  column)  which  occu- 
pies the  base  (cervix)  of  the  posterior  horn  (columna  posterior)  of 
the  cord  from  the  level  of  the  3d  lumbar  to  that  of  the  7th  cervical 
nerve.  The  axones  arising  in  these  cells  pass  to  the  dorso-lateral 
periphery  of  the  lateral  column  (funiculus  lateralis)  up  which  they 
continue  until  they  reach  the  medulla,  then  they  run  up  behind  the 
origins  of  the  Qth,  loth  and  nth  cranial  nerves,  and  then  bend  out- 
wards and  forwards,  entering  the  restiform  body  (inferior  cerebellar 
peduncle)  in  which  they  continue  to  the  cells  in  the  cortex  of  the 
cerebellar  hemisphere  of  th2  same  side  as  that  of  their  origin. 

External  or  Superficial  Arcuate  Fibres,  are  in  two  sets.  The  anterior  set 
of  fibres  are  the  more  numerous,  they  arise  from  cells  in  the  nucleus 
gracilis  and  nucleus  cuneatus,  run  forwards,  and  decussate  in  the  medial 
raphe,  emerge  in  the  anterior  medial  fissure  and  run  outwards  across 
the  surface  of  the  pyramid  and  lower  part  of  the  olive,  then  turn 
upwards  and  enter  the  restiform  body  (inferior  cerebellar  peduncle)  of 
the  side  opposite  to  that  of  their  origin. 

The  posterior  set  of  fibres  also  arise  from  the  cells  in  the  cuneate  and 
gracile  nuclei;  they  run  outwards,  forwards,  and  upwards  directly  into 
the  restiform  body  (inferior  cerebellar  peduncle)  of  the  same  side  as 
that  of  their  origin. 

Internal  or  Deep  Arcuate  Fibres  form  an  intricate  network  situated 
between  the  olives  and  behind  the  pyramids.  Some  of  these  fibres, 
the  olivo-cerebellar  and  cerebello-olivary :,  enter  the  restiform  body  (infe- 
rior cerebellar  peduncle) .  The  remaining  fibres  are  association  or  com- 
missural  fibres  connected  with  the  nuclear  cells  in  the  formatio 
reticularis  of  the  tegmentum  and  the  nuclei  of  the  sensory  cranial 
nerves. 

Fasciculus  Cuneatus, — between  the  restiform  body  and  the  funiculus 
gracilis;  is  the  continuation  of  the  postero-lateral  column  of  the  cord 
(see  lateral  lemniscus,  page  198). 

Fasciculus  Gracilis  (posterior  pyramid), — a  narrow,  white  band,  parallel 
to  and  alongside  the  posterior  fissure;  is  the  continuation  of  the  pos- 
tero-median  column  of  the  cord.  Its  enlarged  upper  extremity  is 
club-shaped  and  called  the  clava  (see  lateral  lemniscus,  page  198). 


THE  BRAIN  211 

Other  Structures  in  the  Medulla.  Internally  the  medulla  is  composed 
of  longitudinal  bundles  of  nerve-fibres,  masses  of  gray  matter  constituting 
nerve  nuclei,  and  nerve-fibres  originating  from  the  nuclei.  The — 

Independent  Nuclei, — are  those  of  the  5th,  8th,  gih,  loth,  nth  and  i2th 
cranial  nerves,  which  arise  in  or  near  the  floor  of  the  4th  ventricle; 
also  the  nucleus  of  the  fasciculus  teres  (eminentia  medialis  or  teres), 
that  of  the  olivary  body,  the  accessory  olivary  nuclei,  and  the  tractus 
solitarius  or  trineural  tract,  the  ascending  root  of  the  gth  nerve. 
Raphe  or  Medial  Septum, — is  situated  in  the  middle  line  of  the  medulla 
above  the  decussation  of  the  pyramids,  and  consists  of  fibres  having 
different  directions  and  of  multipolar  nerve-cells. 

Formatio  Reticularis, — is  a  coarse  network,  situated  within  the  anterior 
and  lateral  regions  of  t^e  medulla,  and  is  formed  by  the  breaking  up  of 
the  anterior  gray  matter  by  the  white  fibres  of  the  crossed  pyramidal 
(cerebro-spinal)  tracts. 

The  Fourth  Ventricle,  or  Ventricle  of  the  Cerebellum,  is  a  diamond- 
shaped  cavity  lying  between  the  cerebellum  and  the  posterior  surface  of 
the  pons  Varolii  and  medulla  oblongata.  Its  upper  angle  is  on  a  level  with 
the  upper  border  of  the  pons,  it  corresponds  with  the  lower  opening  of  the 
cerebral  aqueduct  of  Sylvius,  by  which  this  ventricle  communicates  with  the 
3d  ventricle.  Its  lower  angle  is  on  a  level  with  the  lower  border  of  the 
olivary  body  (oliva),  it  is  continuous  with  the  central  canal  of  the  spinal 
cord,  and  is  called  the  calamus  scriptorius,  from  its  resemblance  to  the 
point  of  a  pen.  The  ventricle  is  closed  posteriorly  by  a  layer  of  pia  mater, 
the  tela  choroidea  inferior,  with  its  choroid  plexuses,  in  which  layer  are  3 
openings;  the  foramen  of  Magendie  (metapore),  just  above  the  calamus 
scriptorius  in  the  median  line,  and  the  foramina  of  Key  and  Retzius  at  the 
extremities  of  the  lateral  angles.  Through  these  foramina  the  ventricles  of 
the  brain  communicate  with  the  subarachnoid  space  of  the  brain  and 
spinal  cord.  The  fourth  ventricle  is  bounded  as  follows: — 

Roof, — is  tent-shaped  and  formed  by  superior  peduncles  of  the  cere- 
bellum, the  superior  medullary  velum  or  valve  of  Vieussens,  the  tela 
choroidea  inferior  (see  above)  and  its  choroid  plexus,  the  obex,  and  the 
inferior  medullary  velum. 

Floor, — is  formed  by  the  posterior  surface  of  the  pons  above  and  the 
medulla  below.  It  contains  the  median  furrow,  on  each  side  of  which 
are — the  fasciculus  teres  (eminentia  medialis  or  colliculus  facialis), 
striae  acusticae  (striae  medullares),  conductor  sonorus  (striae  obliquae), 
fovea  superior, fovea inferior,  alacinerea,  tuberculum  acusticum,  locus 
caeruleus,  taenia  violacea,  and  the  eminences  of  origin  of  certain  nerves 
(seepages  212  and  213). 


212  HUMAN   ANATOMY 

Laterally, — in  the  upper  part  are  the  superior  peduncles  of  the  cere- 
bellum; in  the  lower  part,  the  inferior  peduncles  (restiform  bodies) 
fringed  by  the  funiculi  graciles,  their  clavae  and  the  ligulae. 

Parts  named  above,  and  heretofore  undescribed,  are  the — • 

Sulcus  Longitudinalis  Medianus,  —  the  vertical  median  fissure;  from  the 
centre  of  which  on  each  side  emerge  the — • 

Strife  Medullares  or  Stria  Acusticce, — white  fibres  crossing  the  floor  of 
the  ventricle  transversely,  dividing  it  into  two  triangles,  and  passing 
outward  to  the  auditory  nerve.  They  are  the  axons  of  the  nerve- 
cells  of  the  tuberculum  acusticum. 

Conductor  Sonorus  (striae  obliquae), — a  whitish  band  of  fibres  in  no  way 
differing  from  the  striae  medullares  except  that  they  run  from  the  mid- 
line  obliquely  outward  and  forward  instead  of  transversely.  They 
are  not  constant. 

Inferior  Medullary  Velum, — a  thin  layer  of  white  matter,  stretching  over 
the  ventricle  toward  its  lateral  angles. 

Obex  and  Lingula,—<are,  respectively  the  inferior  and  superior  parts  of  a 
little  irregular  ridge,  which  runs  from  the  clava  of  the  funiculus  gracilis 
to  its  fellow  of  the  opposite  side. 

Eminentia  Teres  (colliculus  facialis), — the  prominent  centre  of  a  spin- 
dle-shaped eminence  made  by  an  underlying  bundle  of  white  fibres, 
the  fasciculus  teres,  formed  in  part  by  the  fibres  of  the  facial  nerve. 

Fovea  Superior, — an  angular  depression,  external  to  the  fasciculus  teres 
and  above  the  striae  medullares. 

Locus  Cceruleus, — a  bluish  depressed  area  above  the  fovea  superior. 

Fovea  Inferior, — an  angular  groove,  its  apex  at  the  striae,  its  limbs  diverg- 
ing below,  enclosing  the — 

Ala  Cinerea  or  Trigonum  Vagi, — a  triangular  area,  corresponding  with 
the  nuclei  of  the  vagus  and  glosso-pharyngeal  nerves. 

Eminentia  Cinerea, — a  prominent  elevation  of  the  ala  cinerea. 

Trigonum  Hypoglossi, — a  triangular  area,  internal  to  the  inner  limb  of 
the  fovea  inferior,  and  corresponding  to  the  tract  of  nerve-cells  from 
which  the  hypoglossal  nerve  originates. 

Trigonum  Acustici, — a  triangular  area,  external  to  the  outer  side  of  the 
fovea  inferior,  having  at  its  base  a  prominence,  the  tuberculum 
acusticum, 

Nuclei  of  Origin,  in  the  floor  of  the  4th  Ventricle,  comprise  the  nuclei  of 
the  cranial  nerves  from  the  5th  to  the  i2th  inclusive,  also  vaso-motor, 
cardiac  ancj  respiratory  centres,  Near  the  ventricle,  in  the  anterior  wall 


THE    SPINAL    CORD  21^ 

of  the  aqueduct  of  Sylvius,  are  the  nuclei  for  the  3d  and  4th   nerves. 
Those  in  the  floor  itself  are  as  follows: — 

$lh  Nerve  (trigeminus), — two  groups  of  cells,  extending  the  length  of  the 

medulla  and  alongside  the  aqueduct  of  Sylvius,  the  nuclei  lying  close  to 

the  lateral  recesses  of  the  ventricle. 

6th  Nerve  (abducens), — in  the  upper  part,  close  to  the  median  line. 
^th  Nerve  (facial), — below  and  external  to  the  6th. 
8th  Nerve  (auditory),  2  nuclei,  one  beneath  the  striae,  the  other  just 

outside  the  ventricle. 
gth  Nerve  (glosso-pharyngeal)  and  loth  Nerve  (vagus), — in  the  upper  part 

of  the  ala  cinerea,  near  the  inferior  angle  of  the  ventricle. 
nth  Nerve  (spinal  accessory), — below  the  preceding,  in  the  lower  part  of 

the  ala  cinerea,  and  running  down  into  the  cord  as  low  as  the  6th  cer- 
vical vertebra. 
1 2th  Nerve  (hypoglossal) , — internal  to  the  gth  and  loth  beneath  the 

fasciculus  teres,  and  in  the  trigonum  hypoglossi. 

THE  SPINAL  CORD  (MEDULLA  SPINALIS) 

The  Spinal  Cord  is  that  part  of  the  cerebro-spinal  axis  which  is  situated  in 
the  spinal  canal.     Its  length  is  about  17  or  18  inches,  terminating  at  the 
lower  border  of  the  ist  lumbar  vertebra  in  thefilum  terminate  (16).     It  is 
cylindrical  in  general  form,  with  2  enlargements,  one  in  the  cervical  region, 
the  other  in  the  lumbar.     It  is  composed  of  gray  and  white  matter,  the 
gray  being  inside  (instead  of  outside,  as  in  the  cerebrum),  and  arranged  so 
as  to  present  a  crescentic  appearance  in  horizontal  section,  joined  by  a 
transverse  commissure,  and  the  extremities  forming  the  Anterior  and  Pos- 
terior Horns  (columnae),  from  which  regions  respectively  the  anterior  and 
posterior  roots  of  the  spinal  nerves  have  their  apparent  origin.     The — 
Membranes, — of  the  cord  are  3,  as  in  the  brain:  the  dura  mater,  arach- 
noid, and  pia  mater.     The  Dura  Mater  represents  only  the  meningeal 
or  supporting  layer  of  the  cranial  dura  mater.     It  is  not  adherent  to 
the  spinal  column,  but  is  connected  thereto  by  fibrous  tissue.     The 
Arachnoid  is  arranged  as  on  the  brain,  its  sub-arachnoid  space  being 
filled  with  its  fluid,  for  the  protection  of  the  cord.     The  Pia  Mater  has 
a  fibrous  band  on  each  side,  the  ligamentum  denticulatum  (9),  con- 
necting it  to  the  dura  mater  by  21  serrations. 
Fissures, — number  6,  the  anterior  and  posterior  median,  and  on  each 

side  the  postero-lateral  (n)  and  the  posterior  intermediate. 
Columns  (funiculi),— are  4  in  number,   2  on  each  side  of  the  cord;  a 
small  posterior  column,  and  a  large  antero-lateral  column,  separated 
from  each  other  by  the  postero-lateral  fissure.     The  posterior  col- 


214 


HUMAN    ANATOMY 


FIG.  75- 


umn  is  further  divided  in  its  upper  part,  into  a  postero-median  and  a 
postero-lateral  column,  which  are  separated  from  each  other  by  the 
posterior  intermediate  septum. 

Central  Canal, — a  minute  canal,  barely  visible  to  the  naked  eye,  extends 
the  whole  length  of  the  cord,  originating  above 
in  the  lower  angle  of  the  4th  ventricle  (i)  and 
terminating  below  in  a  somewhat  dilated 
extremity. 

White  Substance  of  the  Cord  consists  of  medul- 
lated  fibres,  mostly  disposed  longitudinally,  but 
some  obliquely  and  transversely,  also  blood-vessels 
and  neuroglia.  The  Neuroglia  supports  the  fibres 
and  cells  of  the  gray  substance  as  well  as  the  fibres 
of  the  white,  and  is  accumulated  in  three  situa- 
tions; on  the  surface  of  the  cord,  beneath  the  pia 
mater;  around  the  central  canal,  as  the  substantia 
gelatinosa  centralis;  as  a  cap  over  the  posterior 
horn  of  gray  matter,  forming  the  substantia  cinerea 
gelatinosa. 

Nerve-tracts  in  the  white  substance  of  the  cord, 
shown  by  investigation  of  pathological  lesions,  as 
extending  along  various  portions  of  the  cord  and 
into  or  from  the  brain,  are  8  in  number,  as 
follows: — 

In   the  antero-lateral  column   (funiculus  antero- 
lateralis)  are  6,  the — 

Direct  Pyramidal  Tract  (fasciculus  cerebro- 
spinalis  anterior), — next  to  the  median  fissure 
and  in  the  upper  part  of  the  cord;  consists 
of  descending  fibres  from  the  motor  area  of 
the  cerebral  cortex  of  the  same  side,  passing 

through  the  pyramid  of  the  medulla,  crossing  in  the  anterior  white 
commissure  of  the  cord,  and  disappearing  about  the  middle  of  its 
thoracic  region  (see  page  196). 

Crossed  Pyramidal  Tract  (fasciculus  cerebro-spinalis  Jateralis), — in  the 
hinder  part  of  the  column;  consists  of  descending  fibres  from  the 
motor  area  of  the  cortex  on  the  opposite  side,  through  the  pyramid 
of  the  medulla,  crossing  in  the  decussation  of  the  pyramids  (see 
page  196). 
Antero-lateral  Ascending  (Gower's)  Tract  (anterior  spino-cerebellar 


THE    SPINAL   CORD  215 

fasciculus), — in  the  anterior  part  of  the  column;  consists  of  ascending 
fibres  arising  from  cells  in  the  posterior  horn,  crossing  in  the  anterior 
gray  commissure,  and  passing  upward  through  the  medulla  and  pons 
to  the  cerebellum  through  its  superior  peduncles  (brachia  conjunc- 
tiva) (see  page  205). 

Direct  Cerebellar  Tract  (dorsal  spino-cerebellar  fasciculus), — behind 
the  preceding,  commencing  in  the  lumbar  region;  consists  of  fibres 
from  cells  in  the  posterior  gray  matter,  ascending  through  the  resti- 
form  body  to  the  cerebellum  (see  page  210). 

Tract  of  Lissaucr  (fasciculus  postero-lateralis) — a  small  tract,  formed  by 
some  of  the  fibres  of  the  posterior  roots  of  the  spinal  nerves,  running 
upward  for  a  short  distance  and  entering  the  posterior  horn  of  gray 
matter. 

Antero-lateral  Ground  Bundle  (fasciculus  proprius  anterior  et  fas- 
ciculus proprius  posterior), — is  the  remaining  part  of  the  column, 
situated  next  to  the  gray  matter  of  the  cord;  contains — longitudinal 
association  fibres,  uniting  cell-groups  of  the  gray  matter  with  each 
other;  fibres  crossing  the  anterior  commissure  from  the  gray  matter 
of  the  opposite  side;  horizontal  fibres  belonging  to  the  anterior  roots  of 
the  spinal  nerves. 
In  the  Posterior  Column  (funiculus  posterior)  are  2  tracts,  the — 

Tract  of  Goll  (fasciculus  gracilis), — next  to  the  posterior  fissure;  con- 
sists of  fibres  from  the  posterior  roots  of  the  spinal  nerves,  ascend- 
ing to  the  medulla  where  they  end  in  the  nucleus  gracilis  (see  page 
198). 

Tract  of  Burdach  (fasciculus  cuneatus), — between  the  preceding  and 
the  gray  matter;  consists  of  fibres  from  the  posterior  roots  of  the  spinal 
nerves,  some  ascending  a  short  distance  and  entering  the  gray  matter, 
others  entering  Coil's  tract  and  passing  to  the  medulla  (see  page 
198). 

Gray  Substance  of  the  Cord  occupies  the  central  portion,  a  transverse 
section  showing  it  in  the  form  of  two  crescents  joined  by  the  gray  commis- 
sure (commissura  grisea).  Each  crescent  has  an  anterior  and  a  posterior 
cornu  or  horn  (columna) ;  a  lateral  horn  being  also  seen  in  the  upper  thoracic 
region.  The  gray  substance  consists  of  nerve-fibres,  nerve-cells,  blood- 
vessels and  connective  tissue.  The — 

Nerve-fibres, — are  found  as  a  dense  interlacement  of  minute  fibrils, 
formed  of  the  axons  and  dendrons  of  the  nerve-cells  and  nerves  of 
larger  size. 

Nerve-cells* — some  form  columns  of  cells  placed  longitudinally,  and 
some  are  scattered  throughout  the  gray  matter. 


2l6 


HUMAN    ANATOMY 


FIG.  76. 


Clarke's  Posterior  Vesicular  Column  (nucleus  dorsalis), — is  a  group  of 
nerve-cells  at  the  base  of  the  posterior  horn  on  its  inner  side,  extend- 
ing from  the  yth  cervical  nerve  to  the  3d  lumbar. 

The  Spinal  Nerves  are  transmitted  from  each 
side  of  the  spinal  cord  through  the  intervertebral 
foramina  of  the  spinal  column,  in  31  pairs,  of 
which  the  cervical  number  8,  the  thoracic  12,  the 
lumbar  5,  the  sacral  5,  and  the  coccygeal  i. 
Each  nerve  arises  by  two  roots;  an  anterior  (13) 
or  motor  root,  and  a  posterior  (10)  or  sensory 
root,  the  latter  being  distinguished  by  a  ganglion, 
the  spinal  ganglion  (12).  These  nerves  are  de- 
scribed separately  infra,  after  the  description  of 
the  cranial  nerves.  The — 

Cauda  Equina  (ly)  (horse's  tail), — is  a  sheaf  of 
nerves  composed  of  the  elongated  roots  of 
the  4  upper  sacral  nerves,  passing  downward 
to  reach  their  respective  foramina  of  exit 
from  the  spinal  canal. 

THE  CRANIAL  NERVES  (NERVI 
CEREBRALES) 


The  Cranial  Nerves  number  12  pairs,  those 
from  the  5th  to  the  i2th  inclusive  having  their 
deep  origin  wholly  or  in  part  from  the  floor  of  the 
4th  ventricle,  and  all,  except  the  first  two,  origi- 
nating in  or  near  that  situation.  Their  super- 
ficial or  apparent  origin  is  their  connection  with 
the  surface  of  the  brain,  their  deep  or  real  origin  lies 
in  some  special  nucleus  of  gray  matter  deeply 

situated  in  the  brain.  After  emerging  from  the  surface  the  nerves  pass 
through  tubular  prolongations  of  the  dura  mater  in  various  foramina  at 
the  base  of  the  skull,  to  their  final  distribution. 

1st  Nerve,  Olfactory  (n.  olfactorius)  (Plate  6),  nerves  of  smell  (fila), 
about  20  in  number,  composed  of  non-medullated  fibres, — arise  from  the 
under  surface  of  the  olfactory  bulb  (see  page  188);  deeply  by  2  white  roots, 
the  medial  root  from  the  area  of  J3roca  and  the  ^callosal  and  sub-callosal 
gyrus;  the  lateral  root  from  the  anterior  perforated  space  (substantia 
perforata  anterior)  and  from  the  union  of  the  temporal  and  uncinate  gyri, 


THE   CRANIAL   NERVES 


217 


and  by  the  middle  gray  root  (trigonum  olfactorium)  from  thej3ptic  thala- 
by  numerous  foramina  in  the  cribriform  plate  of  the  ethmoid 
bone;  to  form  a  plexiform  network  over  the  upper  third  of  the  nasal  septum, 
the  superior  turbinal  process  and  the  adjacent  surface  of  the  ethmoid 
bone,  from  which  branches  are  distributed  to  the  Schneiderian  membrane 
of  the  nose. 

2d  Nerve,  Optic  (n.  opticus)  nerve  of  sight  (Plate  6), — arises  from  the 
optic  commissure  (chiasma  opticum)  (16)  and  tracts  (15);  deeply  from  the 
external  geniculate  body  (corpus 
geniculatum  laterale),  the  pulvinar 
of  the  ojytk:  thalamus,  and  the  upper 
quadrigi-minal  body  (colliculus  su- 
perior) these  being  the  lower  visual 
centres;  also  from  the^neate  and 
lingual  lobules  of  the  occipital  lobe 
(cortical  visual  centres);  exit  by  the 
optic  foramen;  to  the  retina  of  the 
eye.  [This  nerve  and  the  optic  tract 
are  more  fully  described  under  the 
sub-title  Nerves  of  the  Eye.] 


20. 


3d  Nerve,  Motor  Oculi  (n.  oculo- 
motorius)  (Plate  6),  motor  nerve  of 
the  eye-ball,-^omes  from  the  inner 
side  of  the  crus  (peduncle)  cerebri 
(17),  in  front  of  the  pons  (5);  deeply 
from  a  nucleus  in  the  floor  of  the 
aqueduct  of  Sylvius  (aquaeductus 
cerebri) ;  exit  by  the  sphenoidal  (su- 
perior orbital)  fissure;  to  all  the  mus- 
cles of  the  orbit  except  the  superior 
oblique  and  external  rectus,  also 

through  the  ciliary  ganglion  to  the  sphincter  of  the  iris  and  the  ciliary 
muscle. 

4th  Nerve,  Trochlear  or  Pathetic  (n.  trochlearis)  (Plate  6),  motor  of 
the  eye-ball, — arises  from  the  outer  side  of  the  crus  (jpeduncle)  cerebri  (18), 
in  front  of  the  pons;  deeply  from  a  nucleus  in  the  floor  of  the  aqueduct  of 
.Sylvius,  below  that  of  the  3d  nerve  decussates  in  the  superior  medullary 
velum  with  its  companion  nerve \jgU •  by  the  sphenoidal  (superior  orbital) 
fissure;  to  the  superior  oblique  (trochlear)  muscle  of  the  eye-ball  of  the  side 
opposite  to  that  of  its  origin. 


218 


HUMAN    ANATOMY 


5th  Nerve,  Trifacial  or  (n.  trigeminus)  (Plate  7),  nerve  of  sensation 
and  motion, —  arises  by  2  roots  (19)  from  the  side  of  the  pons  Varolii;  deeply 
from  a  nerve-tract  in  the  medulla  oblongata  and  the  locu^caeruleus  (sen- 
sory root),  the  floor  of  the  4th  ventricle  and  the  wall  of  the  cerebral  aque- 
duct of  Sylvius  (motor  root  or  masti- 
cator nerve);  exit  in  3  divisions  by 
the  sphenoidal  fissure,  the  foramen 
rotundum  and  the  foramen  ovale 
respectively.  The  Gasscrian  or  semi- 
lunar  ganglion  (5)  is  situated  on  its 
sensory  root  at  the  origin  of  the 
three  divisions.  This  nerve  resem- 
bles a  spinal  nerve  in  arising  by  two 
roots,  in  having  a  ganglion  on  its  pos- 
terior (sensory)  root,  and  in  its  com- 
pound function.  It  is  the  great  sen- 
sory nerve  of  the  head  and  face, 
and  the  motor  nerve  of  the  muscles 
of  mastication.  Its  divisions  are 
the  ophthalmic,  the  maxillary  and 
the  mandibular  as  follows: — 

OPHTHALMIC     (n.     ophtf  almicus) 
(6),  a  sensory  nerve, — exit    by    the 
sphenoidal  (superior  orbital)  fissure; 
to  the  eye-ball,  lacrimal  gland,  mu- 
cous lining  of  the  eye  and  nasal  fossae,  and  the  skin  of  the  forehead,  eye- 
brow and  nose.     Its  branches  are  the — 


Frontal  (9) 


Nasal  (n) 
or  naso- 
ciliary 


f  Supra-orbital. 

\  Supra-trochlear.     Lacrimal  (10) 


Branches  to  the  gland, 
the  conjunctiva,  and 
the  eyelid. 


Ganglionic,  to  the  ciliary  ganglion. 

Ciliary,  to  the  ciliary  muscles,  iris  and  cornea. 

Infra-trochlear,  to  the  skin  of  the  eyelids  and  side  of  the 

nose,    the    conjunctiva,   lacrimal    sac    and    caruncula 

lacrimalis. 


MAXILLARY  (7),  a  sensory  nerve, — exit  by  the  foramen  rotundum;  to 
the  temple,  cheek,  lower  eyelid,  nose,  lip,  upper  teeth  and  the  spheno- 
palatine  ganglion,  thence  to  the  palate.  Its  branches  are  the — 


THE   CRANIAL   NERVES  2IQ 

Meningeal  (n.  meningeus  medius). 

f  Temporal     (ramus     zygomaticotem- 
Orbital  (n.  zygomaticus)  (20)  (       poralis). 

[  Malar  (ramus  zygomaticofacialis). 

2  Spheno- palatine  (nn.  sphenopalatini). 

2  Posterior  Sup.  Dental  (16)  (rami  alveolares  superiores  posteriores). 

Middle  Superior  Dental  (ramus  alveolaris  superior  medius). 

Anterior  Sup.  Dental  (18)  (ramus  alveolaris  superior  anterior). 

Palpebral  (rami  palpebrales  inferiores). 

Nasal  (rami  nasales  interni). 

Labial  (rami  labiales  superiores). 

MANDIBULAR  (8),  includes  the  masticator  nerve  or  motor  root  of  the  5th, 
and  is  a  nerve  of  motion,  common  sensation  and  special  sense  (taste).  Its 
exit  is  by  the  foramen  ovale.  Its  recurrent  branch  goes  to  the  dura 
mater  and  the  lining  of  the  mastoid  cells;  its  motor  filaments  to  the  muscles 
of  mastication;  its  sensory  ones  to  the  teeth  and  gums  of  the  lower  jaw,  the 
skin  of  the  temple  and  external  ear,  the  lower  face  and  lip,  and  the  anterior 
%  of  the  tongue.  Its  branches  are  the — 


Recurrent  or  meningeal  (n.  spinosus). 
Internal  Pterygoid  (masticator). 
Masseteric  (masticator).       Auriculo-tem- 
Deep  Temporal  2  (masticator),  poral  (26) 
Buccal  (n.  buccinatorius). 
External  Pterygoid  (masticator). 


Br.  to  the  facial  nerve. 

Br.  to  otic  ganglion. 

Ant.  Auricular  2. 

Brs.  to  meatus  auditorius  2 

Articular. 

Parotid. 

Superior  Temporal. 


Lingual  or  Gustatory  (23), — to  the  tongue,  mouth,  gums  and  sub-lingual 
gland:  communicates  with  the  facial,  inferior  dental  and  hypoglossal 
nerves  and  the  sub-mandibular  ganglion. 

I  Mylo-hyoid  (masticator)  (28),   to    that  muscle 
Inferior    alveolar    or  and  digastric. 

Dental  (24)  {  Dental  Brs.  to  the  molar  and  bicuspid  teeth. 

Incisive,  to  the  canine  and  incisor  teeth. 
Mental  (25),  to  the  chin  and  lower  lip. 

6th  Nerve,  Abducent  (n.  abducens)  (Plate  10),  motor  of  the  eyeball, — 
arises  from  the  pyramid  of  the  medulla  oblongata,  close  to  the  pons  (20,  Fig. 
76);  deeply  from  the  floor  of  the  4th  ventricle,  beneath  the  eminentia  teres; 
exit  by  the  sphenoidal  (superior  orbital)  fissure;  to  the  external  rectus 
muscle  of  the  eyeball. 


22O  HUMAN    ANATOMY 

yth  Nerve,  Facial,  Portio  Dura  (n.  facialis)  (Plate  8),  is  the  motor  nerve 
of  the  face,  the  stapedius,  the  muscles  of  the  external  ear  and  other  mus- 
cles. The  Pars  intermedia  (glosso-palatine  nerve)  is  a  sensory  nerve  to  the 
palate  and  its  chorda  tympani  branch  is  the  nerve  of  taste  for  the  anterior 
2a  of  the  tongue,  and  the  vaso-dilator  of  the  sub-mandibular  and  sub- 
lingual  glands.  Cashes,  from  the  upper  part  of  the  medulla  oblongata,  in 
the  groove  between  the  olivary  and  restiform  bodies  (21,  Fig.  76) ;  deeply  in 
the  floor  of  the  4th  ventricle,  from  a  nucleus  in  the  lower  part  of  the  pons 
near  that  of  the  6th  nerve;  the  Pars  Intermedia  takes  its  deep  origin  from 
the  Solitary  Tract;  exit  by  the  internal  auditory  meatus,  through  the 
aqusductus  (canalis  facialis)  Fallopii  and  the  stylo-mastoid  foramen;  to 
the  muscles  of  expression  of  the  face,  those  of  the  ear,  etc.,  and  to  the 
tongue.  Behind  the  ramus  of  the  jaw  its  diverging  branches  form  the  pes 
anserinus  or  goose's  foot.  It  communicates  with  the  meningeal  sympa- 
thetic plexus  by  the  external  superficial  petrosal  nerve;  with  the  spheno- 
palatine  and  otic  ganglia,  by  the  large  and  small  superficial  petrosal  nerves ; 
with  the  auditory,  great  auricular,  auriculo-temporal,  pneumogastric  (n. 
vagus),  glosso-pharyngeal,  small  occipital,  and  superficial  cervical  nerves, 
the  three  divisions  of  the  5th  nerve,  and  the  carotid  plexus.  The  petrosal 
nerves  mentioned  above  are  given  off  by  the  geniculate  ganglion,  a  swelling 
on  the  ;th  nerve  in  the  aquaeductus  (canalis  facialis)  Fallopii  (described 
separately).  Its  branches  of  distribution  are  the — 

Tympanic, — to  the  stapedius  muscle. 

Chorda  Tympani, — nerve  of  taste,  etc.  (see  above). 

Posterior  Auricular, — dividing  into  Auricular  and  Occipital. 

Digastric, — to  that  muscle. 

Stylo-hyoid, — to  that  muscle. 

j  Temporal  Brs.  to  the  temporal  region. 

Temporo-facial     {  Malar  Brs.  to  the  occip.-frontalis  and  the  lower  eyelid. 
[  Infra-orbital  /  Superficial  Brs. 
\  Deep  Brs. 

{Buccal  Brs.  to  the  mouth  and  cheek  muscles. 
Mandibular  Brs. 
Cervical  Brs. 

8th  Nerve,  Auditory,  Portio  Mollis  (n.  acusticus)  (Plate  10),  the  special 
nerve  of  the  sense  of  hearing,  is  soft  in  texture  and  destitute  of  neurilemma. 
-arises  from  the  groove  between  the  pons  and  medulla,  between  the  resti- 
form body  and  the  7th  nerve  (22,  Fig.  76);  deeply  from  thejSflQr  of  the  ^th 
ventricle  by  2  roots,  one  from  the  trigonum  acustici,  the  other  from  the  ac- 


THE   CRANIAL    NERVES  221 

cessory  nucleus  and  the  tuberculum  acusticum.  Goes  by  the  internal 
auditory  meatus;  to  the  internal  ear.  It  is  the  only  cranial  nerve  which 
does  not  leave  the  cranium.  Its  branches  are  two,  the — 

Vestibular,  to  the  vestibule.     Qochlear,  to  the  cochlea  (see  page    309). 

2J*  j  9th  Nerve,  Glosso-pharyngeal  (n.  glosso-pharyngeus)  (Plate  9)  ^sensory 

*      nerveTand  nerve  of  taste, — arises  by  3  or  4  filaments  from  the  medulla 

oblongata  in  the  groove  between  the  olivary  and restiform  bodies  (24,  Fig. 

76);  deeply  from  a  nucleus  in  the  floor  of  the  4th  ventricle  and  the  tractus 

or  fasciculus  solitarius  in  the  lower  part  of  the  medulla;  exit  by  the  jugular 

.foramen;  to  the  mucous  membrane  of  the  fauces  and  base  of  the  tongue, 

and  the  mucous  glands  of  the  mouth  and  tonsil.     It  communicates  with  the 

facial,  pneumogastric  (vagus)  and  sympathetic  nerves.     Its  branches  of 

distribution  are  the — 

Tympanic  or  Jacobson's  Nerve, — described  under  Ear  (see  page  302). 

Carotid  Branches, — along  the  internal  carotid  artery. 

Pharyngeal, — to  the  pharyngeal  plexus. 

Muscular, — to  the  stylo-pharyngeus  muscle. 

Tonsillar  Branches, — forming  the  tonsillar  plexus,  thence  to  the  soft 
palate  and  fauces. 

Lingjiql  2,— one  to  the  base,  the  other  to  the  posterior  half  of  the  tongue, 
being  distributed  to  the  mucous  membrane,  the  papillae  and  the  fol- 
licular  glands. 

loth  Nerve,  Pneumogastric  (n.  vagus)  (Plate  9), — the  auriculo-laryngo- 
pharyngo-cesophago-tracheo-pulmono-cardio-gastro-hepatic  nerve  (Pan- 
•  coast),  is  composed  of  both  motor  and^ensory  fibres.  It  arises  by  8  or  10 
filaments  from  the  medulla  oblongata  (25,  Fig.  76) ,  between  the  olivary  and 
restiform  bodies;  deeply  from  the  nucleus  vagi  in  the  floor  of  the  4th  ven- 
tricle, the  tractus  or  fasciculus  solitarius  and  the  nucleus  ambiguus  in  the 
medulla;  exit  by  the  jugular  foramen;  and  is  distributed  to  the  parts  and 
organs  named  in  the  afjove  euphonious  appellation;  supplying  sensory  and 
motor  fibres  to  the  organs  of  voice  and  respiration,  and  motor  fibres  alone 
to  the  pharynx,  cesophagus,  stomach  and  heart.  It  has  a  ganglion  on  its 
root  and  another  on  its  trunk,  thereby  communicating  with  the  7th,  gth, 
nth  and  i2th  cranial  nerves,  the  ist  and  2nd  cervical  nerves  and  the  sym- 
pathetic. Its  branches  of  distribution  are  the— 

Meningeal  (ramus  meningeus), — a  recurrent  filament  to  the  dura  mater. 

Auricular  (ramus  auricularis)  or  Arnold's  Nerve, — to  the  external  ear. 

Pharyngeal  (ramus  pharyngeus), — to  the  pharyngeal  plexus. 

Superior  Laryngeal  (n.  laryngeus  superior), — a  nerve  of  sensation  to  the 
larynx,  dividing  into  the  External  (ramus  externus)  and  Internal 
(ramus  internus)  Laryngeal. 


222  HUMAN    ANATOMY 

Recurrent  Laryngeal  (n.  laryngeus  inferior), — the  motor  nerve  of  the 
larynx;  gives  off  cesophageal,  tracheal  and  pharyngeal  branches. 

Cervical  Cardiac  Branches  (rami  cardiaci  superiores), — to  the  cardiac 
plexuses. 

Thoracic  Cardiac  Branches  (rami  cardiaci  inferiores), — 10  the  deep  car- 
diac plexus. 

Anterior  Pulmonary  Branches, — to  that  plexus. 

Posterior  Pulmonary  Branches, — to  that  plexus. 

(Esophageal  Branches  (rami  cesophagei), — to  the  cesophageal  plexus. 

Gastric  (rami  gastric), — on  the  left  side  to  the  anterior  surface  of  the 
stomach,  on  the  right  side  to  the  posterior  surface;  some  filaments 
going  to  the  hepatic  plexus. 

i  ith  Nerve,  Spinal  Accessory  (n.  accessorious)  (Plate  9),  a  motor  nerve; 
consists  of  the  two  parts,  the  accessory  (ramus  internus)  to  the  vagus  and 
the  spinal  portion  (ramus  externus).  The  Accessory  or  Bulbar  portion 
(ramus  internus)  arises  by  4  or  5  filaments  from  the  medulla  below  the 
vagus  (26,  Fig.  76);  deeply  from  the  nucleus  ambiguus  and  the  column 
of  cells  underneath  the  ala  cineria  in  the  floor  of  the  4th  ventricle;  exit 
by  the  jugular  foramen;  to  the  pharyngeal  and  superior  laryngeal  branches 
of  the  vagus  and  through  the  former  probably  supplying  the  muscles  of 
the  soft  palate.  The  Spinal  portion  (ramus  externus)  arises  by  several 
filaments  from  the  lateral  tract  of  the  cord  behind  the  anterior  roots  of  the 
upper  five  cervical  spinal  nerves;  deeply  from  the  dorso-lateral  gray  tract 
of  the  cord  from  the  olive  down  to  the  level  of  the  5th  cervical  nerve;  exit 
by  the  jugular  foramen,  having  first  entered  the  skull  by  the  foramen  mag- 
num; to  the  sterno-mastoid  and  trapezius  muscles,  forming  plexuses  with 
the  2d,  3d  and  4th  cervical  nerves. 

1 2th  Nerve,  Hypoglossal  (n.  hypoglossus),  Nonus  or  Ninth  of  Willis 
(Plate  10),  the  motor  nerve  of  the  tongue, — arises  by  10  to  15  filaments 
from  the  medulla  oblongata  in  the  groove  between  the  pyramid  and  the 
olivary  body  (2  7,  Fig.  76);  deeply  from  the  trigonum  hypoglossi  in  the  floor 
of  the  4th  ventricle;  exit  by  the  anterior  condylar  foramen  (canalis  hypo- 
glossi) in  two  bundles;  to  certain  muscles  of  the  tongue  and  other  muscles; 
communicating  with  the  vagus,  sympathetic,  ist  and  2d  cervical  and  the 
lingual.  Its  branches  of  distribution  are  the — 

Meningeal  Branches, — to  the  dura  mater. 

Descendens  Hypoglossi  (ramus  descendens), — to  the  sterno-hyoid, 
sterno-thyroid  and  omohyoid  muscles;  joins  the  communicans  hypo- 
glossi branch  of  the  cervical  plexus. 

Thyro-hyoid  (ramus  thyreohyoideus), — to  the  thyro-hyoid  muscle. 


GANGLIA    OF    CRANIAL   NERVES  223 

Muscular  Branches, — to  the  stylo-glossus,  hyo-glossus,  genio-hyoid  and 
genio-hyo-glossus  muscles,  and  to  the  intrinsic  muscles  of  the  tongue 
(rami  linguales). 

Nerves  entering  the  Cranium  before  passing  out  of  it,  are  the  spinal 
portion  (ramus  externus)  of  the  spinal  Accessory  (n.  accessorius),  and  the 
Nasal  branch  (n.  nasociliaris)  of  the  Ophthalmic  division  of  the  5th  nerve. 
The  first  enters  by  the  foramen  magnum,  and  leaves  by  the  jugular  fora- 
men. The  second  enters  from  the  orbit  by  the  anterior  ethmoidal  fora- 
men (canalis  ethmoidale  anterius),  and  leaves  by  the  nasal  slit  at  the  side 
of  the  crista  galli. 

GANGLIA  OF  THE  CRANIAL  NERVES 

Ganglia  are  on  and  connected  with  several  of  the  cranial  nerves.  Those 
connected  with  the  5th  nerve  have  each  motor,  sensory  and  sympathetic 
roots.  The  various  ganglia  are  named  and  connected  as  follows: — 

With  the  $d  Nerve, — the  ophthalmic,  lenticular,  or  ciliary  ganglion  (gan- 
glion ciliare). 

On  the  Fifth  Nerve, — the  Gasserian  or  semilunar  ganglion. 

With  the  5/A  Nerve, — the  ophthalmic  (ganglion  ciliare),  the  spheno- 
palatine  (Meckel's),  the  otic,  and  the  sub-mandibular  or  sub-maxil- 
lary ganglia. 

On  the  ith  Nerve, — the  geniculate  ganglion  (ganglion  geniculi)  or  intu- 
mescentia  ganglioformis. 

With  the  ith  Nerve, — the  spheno-palatine  (Meckel's)  ganglion,  and  the 
otic  ganglion. 

With  the  Cochlear  portion  (radix  cochlearis]  of  the  8th  Nerve, — the  spiral 
ganglion. 

With  the  Vestibular  portion  (radix  vestibularis]  of  the  &th  Nerve, — the 
vestibular  ganglion  (Scarpa's). 

On  the  Qth  Nerve, — the  jugular  (ganglion  superius)  and  petrous  (ganglion 
inferius)  ganglia. 

On  the  loth  Nerve, — the  jugular  or  ganglion  of  the  root  (ganglion 
jugulare),  and  the  inferior  or  ganglion  of  the  trunk  (ganglion  nodo- 
sum). 

With  the  nth  Nerve, — the  jugular  ganglion  (ganglion  jugulare)  of  the 
loth  nerve  is  connected  with  the  accessory  portion  (ramus  internus) 
of  the  nth. 

Gasserian  or  Semilunar  Ganglion  (Plate  7),  on  the  sensory  root  of  the 
5th  nerve,  is  situated  near  the  apex  of  the  petrous  portion  of  the  temporal 
bone.  It  communicates  with  the  carotid  plexus  of  the  sympathetic  by 
filaments  on  its  inner  side.  Its  branches  are  the  3  divisions  of  the  sth 


224  HUMAN   ANATOMY 

nerve,  the  ophthalmic,  maxillary,  and  mandibular,  the  latter  trunk  being 
joined  by  the  motor  root  (masticator  nerve)  of  the  nerve  outside  the  cra- 
nium. The  ganglion  also  gives  off  minute  branches  to  the  tentorium 
cerebelli  and  the  dura  mater  in  the  middle  cranial  fossa. 

Ophthalmic,  Ciliary,  or  Lenticular  Ganglion  (ganglion  ciliare)  (Plate 
6),  is  about  the  size  of  a  pin's  .head,  and  is  situated  at  the  back  of  the 
orbit.  Its  roots  are  3  in  number, — a  sensory  (radix  longa  ganglii  ciliaris), 
from  the  nasal  branch  (n.  nasociliaris)  of  the  ophthalmic;  a  motor  root 
(radix  brevis  ganglii  ciliaris),  from  the  3d  nerve;  and  a  sympathetic  root 
(radix  sympathetica  ganglii  ciliaris),  from  the  cavernous  plexus.  Its 
branches  are  the  short  ciliary  nerves  (nn.  ciliares  breves),  to  the  ciliary 

muscle,  the  iris  and  the  cornea. 
^3¥ 
Spheno-palatine  or  Meckel's  Ganglion  (Plate  7),  the  largest  of  the 

cranial  ganglia,  is  situated  in  the  spheno-palatine  or  pterygo-maxillary 
fossa,  close  to  the  spheno-palatine  foramen.     Its  roots  are — a  sensory, 
from  the  maxillary  nerve;  a  motor,  from  the  facial,  through  the  large 
superficial  petrosal  (n.  petrosus  superficialis  major);  and  a  sympathetic 
root,  from  the  carotid  plexus,  through  the  large  deep  petrosal  (n.  petrosus 
profundus);  the  two  last-named  joining  to  form  the  Vidian  nerve   (n. 
canalis  pterygoidei)  before  entering  the  ganglion.     Its  branches  are  the — 
Ascending  Branches  (rami  orbitales), — to  the  orbit. 
Anterior  or  Large  Palatine  (n.  palatinus  anterior), — to  the  gums  and 

hard  palate. 
Middle  or  External  Palatine  (n.  palatinus  medius), — to  the  uvula,  tonsil 

and  soft  palate. 
Posterior  or  Small  Palatine   (n.   palatinus  posterior), — to  the  levator 

palati  and  azygos  uvulae  muscles,  the  soft  palate,  tonsil  and  uvula. 
Superior  Nasal  Branches  (rami  nasales  posteriores  superiores), — to  the 
mucous  membrane  of  the  superior  and  middle  turbinal  processes  and 
that  lining  the  posterior  ethmoidal  cells. 
Naso-palatine  (n.  nasopalatinus), — to  the  mucous  membrane  behind 

the  incisor  teeth,  and  that  of  the  septum  of  the  nose. 
Pharyngeal  or  Ptery go- palatine, — to  the  mucous  membrane  of  the  upper 

part  of  the  pharynx. 

Posterior    Nasal   Branches    (rami    nasales    posteriores    inferiores), — to 
the   mucous  membrane  at  the  back  of  the  roof  of  the  mouth,  and 
that  of  the  septum  and  superior  meatus  of  the  nose. 

Otic  Ganglion  (ganglion  oticum),  Arnold's  (Plate  7),  is  situated  on  the 
inner  surface  of  the  mandibular  nerve,  immediately  below  the  fora- 
men ovale.  Its  roots  are — a  sensory,  from  probably  the  glosso-pharyngeal; 


GANGLIA    OF    CRANIAL    NERVES  225 

a  motor,  from  probably  the  facial;  both  through  the  small  superficial 
petrosal  (n;  petrosus  superficial  minor)  continued  from  the  tympanic 
plexus;  and  a  sympathetic  root  from  the  middle  meningeal  plexus.  It 
communicates  also  with  the  internal  pterygoid  branch  of  the  mandibular, 
and  with  the  auriculo-temporal.  Its  branches  are — a  filament  (n.  tensoris 
tympani)  to  the  tensor  tympani  muscle,  one  (n.  tensoris  veli  palatini)  to 
the  tensor  palati,  and  one  to  the  chorda  tympani  nerve. 

Sub -mandibular  or  Sub-maxillary  Ganglion  (Plate  7)  is  situated  above 
the  sub-maxillary  gland.  Its  roots  are — a  sensory  (rami  communicantes 
cum  n.  linguali),  from  the  lingual  branch  of  the  mandibular;  a  motor, 
from  the  facial  by  the  chorda  tympani;  and  a  sympathetic  root  from  the 
facial  plexus.  Its  branches  (rami  sub- 

maxillares)  are  5  or  6  in  number,  dis-  IG>  79> 

tributed  to  the  mucous  membrane  of 
the  mouth,  Wharton's  duct  (ductus 
sub-maxillaris),  and  thesub-mandibular 
or  sub-maxillary  gland. 

Geniculate  Ganglion  (ganglion  gen- 
iculi)  (2)  or  Intumescentia  Ganglio- 
formis  (Plate  8),  is  a  reddish,  gangli- 
form  swelling  on  the  yth  or  facial 
nerve,  situated  in  the  aquasductus 
Fallopii  (canalis  facialis),  above  the 
tympanum  and  near  the  Gasserian 
ganglion  (ganglion  semilunare).  It 
communicates  with  the  spheno-pala- 
tine  ganglion,  the  otic  ganglion  and 

the  meningeal  plexus  of  the  sympathetic,  by  the  3  superficial  petrosal 
nerves,  which  are  seen  on  removing  the  Gasserian  ganglion  (ganglion  semi- 
lunare) (7),  as  follows: — 

Large  Superficial  Petrosal  (3), — passes  through  the  hiatus  Fallopii 
(hiatus  canalis  facialis),  thence  across  the  foramen  lacerum  medium 
to  the  Vidian  canal  (canalis  pterygoidei)  where  it  joins  the  large  deep 
petrosal  from  the  carotid  plexus,  to  form  the  Vidian  nerve  (n.  canalis 
pterygoidei),  as  which  it  goes  to  Meckel's  ganglion  (ganglion  spheno- 
palatinum)  (page  224),  forming  its  motor  root. 

Small  Superficial  Petrosal  (4), — immediately  external  to  the  preceding, 
going  from  the  geniculate  ganglion  of  the  yth  to  the  otic  ganglion, 
lying  directly  over  the  tensor  tympani  muscle. 

External  Superficial  Petrosal  (5), — going  from  the  7th   nerve   to  the 
sympathetic  plexus  on  the  middle  meningeal  artery  (6). 
IS 


226  HUMAN   ANATOMY 

The  Vidian  Nerve  (n.  canalis  pterygoidei)  (Plate  8),  is  a  short  nerve 
of  communication,  between  the  facial  and  sympathetic  on  the  one  hand, 
and  the  spheno-palatine  ganglion  on  the  other,  supplying  that  ganglion 
with  its  motor  and  vaso-motor  roots.  It  is  formed  by  the  junction  of 
the— 

Large  Superficial  Petrosal,  br.  of  the  facial  (p.  220),  with  the — 

Large  Deep  Petrosal,  br.  of  the  carotid  plexus  (p.  237),  which  tunnels  the 
cartilage  filling  in  the  foramen  lacerum  medium  (p.  41).  It  then  en- 
ters the  Vidian  canal  (canalis  pterygoidei)  (p.  25)  in  the  pterygoid 
process  of  the  sphenoid  bone,  passing  through  which  it  finally  joins 
the  posterior  part  of  the  spheno-palatine  ganglion  (p.  224). 

Ganglia  of  the  pth  Nerve  (Plate  9).  The  Jugular  Ganglion  (ganglion 
superius)  is  regarded  as  a  segmentation  from  the  petrous  ganglion  (gan- 
glion inferius)  below.  The  Petrous  Ganglion  (ganglion  inferius)  is  situated 
in  a  depression  on  the  lower  border  of  the  petrous  portion  of  the  temporal 
bone.  From  it  arise  the  filaments  which  connect  the  gth  nerve  with  the 
loth  and  the  sympathetic;  and  it  communicates  also  with  the  yth  nerve. 
Its  branches  of  distribution  are  the  tympanic,  carotid,  pharyngeal,  muscu- 
lar, torisillar,  and  lingual  branches  of  the  gth  nerve  (see  page  221). 

Ganglia  of  the  loth  Nerve  (Plate  9).  The  Ganglion  of  the  Root  (gan- 
glion jugulare)  is  connected  by  filaments  with  the  accessory  portion 
(ramus  internus)  of  the  nth  nerve,  with  the  petrous  (inferior)  ganglion 
of  the  9th,  with  the  yth,  and  with  the  sympathetic.  The  Ganglion  of  the 
Trunk  (ganglion  nodosum)  involves  all  the  fibres  of  the  nerve,  as  also  the 
accessory  portion  (ramus  internus)  of  the  nth,  which  passes  through  it. 
It  is  connected  with  the  1 2th  nerve,  the  superior  cervical  ganglion  of  the 
sympathetic,  and  the  loop  between  the  ist  and  2d  cervical  nerves. 

THE  SPINAL  NERVES  (NERVI  SPINALES) 

The  Spinal  Nerves  number  31  pairs,  of  which  the  cervical  number  8, 
the  thoracic  12,  the  lumbar  5,  the  sacral  5,  and  the  coccygeal  i.  All  the 
cervical  nerves  escape  above  the  corresponding  vertebrae  except  the  8th 
which  emerges  between  the  jth  cervical  and  ist  thoracic  vertebrae,  each 
of  the  others  below  the  corresponding  vertebrae,  through  the  intervertebral 
foramina.  Each  nerve  arises  by  2  roots, — an  anterior  motor  root  (effer- 
ent), and  a  posterior  sensory  one  (afferent),  the  latter  having  a  ganglion 
on  it,  the  spinal  ganglion,  situated  in  the  intervertebral  foramen.  The 
roots  unite,  and  the  spinal  nerve  thus  formed  divides  into  2  divisions  (rami), 
each  having  motor  and  sensory  fibres.  Just  before  this  division  takes 


THE    SPINAL    NERVES  227 

place,  each  nerve  gives  off  a  minute  gray  ramus  communicans,  which 
after  being  joined  by  a  branch  of  the  sympathetic,  re-enters  the  spinal 
canal  and  is  distributed  to  the  spinal  cord  (medulla  spinalis)  and  its 
meninges,  these  are  called  recurrent  meningeal  nerves.  The  posterior 
divisions  (rami)  are  small  and  generally  unimportant;  they  supply  the 
muscles  and  integument  of  the  back.  The  anterior  divisions  (rami) 
supply  the  neck,  front,  and  sides  of  the  trunk,  and  the  extremities;  unit- 
ing in  various  regions  to  form  plexuses,  from  which  important  nerve- 
trunks  originate.  Each  anterior  division  (ramus),  from  2d  thoracic  to  2d 
lumbar  inclusive,  is  connected  by  a  slender  filament  with  the  sympathetic. 
These  are  called  splanchnic  branches  or  "white  rami  communicantes ;  there 
is  a  second  set  of  them  given  by  the  2d  and  3d  or  by  the  3d  and  4th  sacral 
nerves. 

THE  CERVICAL  NERVES 

The  Cervical  Nerves  (Plate  n),  are  8  in  number.  The  anterior  divi- 
sions of  the  4  upper  form  the  cervical  plexus;  the  anterior  divisions  of  the 
lower  4,  together  with  the  ist  thoracic,  form  the  brachial  plexus.  The 
posterior  division  (ramus)  of  the  ist  cervical,  the  suboccipital  nerve, 
differs  from  the  others  in  not  dividing  into  internal  and  external  branches. 
It  gives  off  a  communicating  branch,  to  the  second  cervical,  and  5  muscular 
branches.  The  posterior  division  (ramus)  of  the  2d  cervical  is  much 
larger  than  the  anterior,  it  is  called  the  Great  Occipital  (n.  occipitalis 
magnus),  a  cutaneous  nerve. 

The  Cervical  Plexus  (plexus  cervicalis)  (Plate  n),  is  formed  by  the 
anterior  divisions  of  the  upper  4  cervical  nerves.  It  is  situated  opposite 
the  upper  4  cervical  vertebrae,  resting  on  the  levator  anguli  scapulae  (m. 
levator  scapulae)  and  scalenus  medius  muscles  and  covered  in  by  the  sterno- 
mastoid.  Its  branches  number  10,  of  which  the  first  4  are  superficial  and 
the  last  6  are  deep,  as  follows: 

Occipitalis  Minor  (n.  occipitalis  minimus), — ascending  to  the  back  of 
the  side  of  the  head. 

(  Facial,  to  the  skin  over  the  parotid  gland. 

Auricularis  Magnus   \  Auricular,  to  the  skin  of  the  pinna,  concha,  etc. 
I  Mastoid,  to  the  integument  behind  the  ear. 

Superficial  Cervical  (n.  cutaneous  colli), — by  2  branches  to  the  skin  of 
the  neck. 


228  HUMAN   ANATOMY 


Supraclavicular 


Suprasternal   (nn.  supraclaviculares  anteriores), — to 

the  skin  of  that  region. 
Supraclavicular    (nn.    supraclaviculares    medii), — to 

the  skin  over  the  pectoral  and  deltoid. 
Supra-acromial  (nn.  supraclaviculares  posteriores), — 

to  the  skin  of  the  shoulder. 


Communicating, — brs.   to  the    loth   (vagus),    i2th   (hypoglossal)    and 
sympathetic  nerves. 

Muscular, — to  the  anterior  recti  and  rectus  lateralis  muscles. 

Communicantes  Hypoglossi  2,  join  the  descendens  hypoglossi  nerve. 

Phrenic, — is  described  below. 

Deep  Communicating, — to  the  spinal  accessory  nerve. 

Deep    Muscular, — to    the    sterno-mastoid,    trapezius,    levator    anguli 
-  ^scapulas  (m.  levator  scapulae)  and  scalenus  medius  muscles. 

The  Phrenic  Nerve  (nervus  phrenicus),  or  Internal  Respiratory  of  Bell, 
arises  by  3  heads  from  the  3d,  4th,  and  5th  cervical,  descends  across  the 
front  of  the  scalenus  anticus  (m.  scalenus  anterior),  crossing  the  sub- 
clavian  and  internal  mammary  arteries  in  the  middle  mediastinum,  and  is 
distributed  to  the  inferior  surface  of  the  diaphragm.  It  sends  filaments 
to  the  pericardium  and  pleura,  and  communicates  with  the  solar  and 
phrenic  plexuses  of  the  sympathetic  in  the  abdomen.  On  the  right  side 
of  the  body  it  is  situated  more  deeply,  and  is  shorter  and  more  vertical  in 
direction  than  on  the  left  side.  In  the  thorax  each  phrenic  nerve  is 
accompanied  by  the  comes  nervi  phrenici  artery,  a  branch  of  the  internal 
mammary. 

The  Brachial  Plexus  (plexus  brachialis)  (Plate  12),  is  formed  by  the 
union  of  the  anterior  division  of  the  four  lower  cervical  nerves  and  the  first 
thoracic.  The  5th,  6th  and  7th  cervical  unite  into  one  trunk  externally 
to  the  scalenus  medius,  as  also  do  the  8th  cervical  and  ist  thoracic  behind 
the  same  muscle.  Below  the  line  of  the  clavicle  both  these  trunks  bifur- 
cate; the  two  adjacent  branches  unite  behind  the  axillary  artery  making 
the  Posterior  Cord,  and  the  remaining  2  form  the  Outer  (lateral)  and  Inner 
(medial)  Cords,  as  referred  to  the  artery.  Each  of  these  cords  bifurcates, 
but  the  2  adjacent  branches  of  the  outer  and  inner  cords  unite  over  the 
artery,  to  form  the  Median  Nerve,  leaving  4  other  branches, — the  Ulnar, 
derived  from  the  inner  cord,  iheMusculo-cutaneous  (n.  musculocutaneus), 
from  the  outer  cord,  and  the  Musculo-spiral  (n.  radialis)  and  Circumflex 
(n.  axillaris)  from  the  posterior  cord.  (See  Plate  12.) 

THE  BRANCHES  of  the  brachial  plexus  are  as  follows: — 
Above  the  clavicle  are  given  off  4,  the — 


THE    SPINAL   NERVES  2  29 

/J   Communicating, — completing  the  phrenic  nerve. 

*  /  Musctttar,  to  The  longus    colli,  scaleni,   rhomboidei,  and    subclavius 
/       muscles.     The  branch  actuating  the  rhombcidei  and  levator  anguli 
scapulae   (n.    levator    scapulae)    is    sometimes  called    the  posterior 
.     scapular  (n.  dorsalis  scapulae). 

/  Posterior,  or  Long  Thoracic  (n.  thoracalis  longus),  external  respiratory 
'        nerve  of  Bell, — -to  the  serratus  magnus,  arising  from  the  5th,  6th  and 

.       7th  cervical. 
/  Suprascapular, — from  the  ist  trunk  of  the  plexus,  to  the  supra-  and  in- 

fra-spinatus  muscles  and  the  shoulder-joint. 
Below  the  clavicle  are  12,  namely,  the — 
/)  Anterior  Thoracic  2, — external  (lateral)  and  internal  (medial)  from  the 

outer  (lateral)  and  inner  (medial)  cords,  to  the  pectoral  muscles. 
Subsca pular  3, — from  the  posterior  cord,  to  the  subscapularis,  teres 
major  and  latissimus  dorsi  muscles.     The  long  sw&scapular  is  also 
called  nervus  thoracodorsalis. 
2,  j  Circumflex  (n.  axillaris), — from  the  posterior  cord,  to  the  muscles  and 

integument  of  the  shoulder,  and  the  shoulder-joint. 
JMusculo-cutaneous   (n.    musculocutaneus), — from    the  outer  cord,   to 
the  forearm  externally,  piercing  the  coraco-brachialis  muscle.      Its 
cutaneous  branch  is  also  called  nervus  cutaneus  antibrachii  lateralis. 
'     Internal  Cutaneous  (n.  cutaneus  antibrachii  medialis), — from  the  inner 

cord,  to  the  arm  and  forearm. 

Lesser  Internal  Cutaneous  (n.  cutaneus  brachii  medialis)  nerve  of  Wris- 
berg, — from  the  inner  cord,  to  the  back  of  the  arm.     Is  sometimes 
.    wanting,  sometimes  connected  with  the  intercosto-humeral. 
V  : Median  (n.  medianus), — from  outer  (lateral)  and  inner  (medial)  cords, 
passes  between  the  two  heads  of  the  pronator  radii  teres  (m.  pronator 
teres),  supplying  the  pronators,  flexors,  first  2  lumbricales,  and  the 
integument  of  the  thumb,  2^  fingers,  and  the  radial  side  of  the  palm. 
Its  branches  are  all  in  the  forearm,  except  its  terminals  in  the  palm  of 
the  hand,  and  are  named  the — 
Muscular. 

Anterior  Interosseous  (n.  interosseus  antibrachii  volaris). 
Palmar  Cutaneous  (n.  ramus  cutaneus  palmaris  n.  mediani). 
.  f  Br.  to  thumb  muscles. 
\  Digital,  (nn.  digitales  volares  communes)  to  thumb  and  index. 

J  Digital  (nn.  digitales  volares  proprii)   to  thumb,  and  2^ 
lntcrn.3,1    \     /. 

(    fingers. 

Ulnar, — from  the  inner  (medial)  cord,  passes  between  the  two  heads  of 


230  HUMAN   ANATOMY 

the  flexor  carpi  ulnaris  at  the  inner  condyle  of  the  humerus,  supplying 
the  elbow- and  wrist-joints,  several  muscles,  and  the  palmar  and  dorsal 
integument  of  the  little  finger  and  half  of  the  ring  finger.  Branches 
are  the — 

Articular  (elbow).     Dorsal  Cutaneous.         Superficial  Palmar. 
Muscular.  Articular  (wrist).  Deep  Palmar. 

Cutaneous. 

.  I  Musculo-spird  (n.  radialis), — from  the  posterior  cord,  accompanies  the 

/      superior  profunda  artery  and  vein  in  the  spiral  groove  of  the  humerus, 

and  in  front  of  the  outer  (lateral)  condyle  it  divides  into  the  radial 

(ramus  superficialis  n.  radialis)   and  posterior  interosseous  (ramus 

prof  undus  n.  radialis)  nerves.     Its  branches  are — 

Muscular  (rami  musculares  n.  radialis)  divided  into  internal  (medial) 
posterior,  and  external  (lateral). 

Cutaneous  (rami  collaterals  n.  radialis)  one  internal  (n.  cutaneus 
brachii  posterior)  and  two  external  (n.  cutaneous  brachii  posterior, 
ramus  proximalis  et  ramus  distalis). 

Radial  (ramus  superficialis  n.  radialis)  divides  into  an  external  and  an 
internal  branch,  the  latter  giving  off  4  digital,  to  the  ulnar  side  of  the 
thumb  and  the  adjacent  sides  of  2^  fingers.  Communicating  branch 
to  ulnar  (ramus  anastomoticus  ulnaris). 

Posterior  Interosseous  (ramus  prof  undus  n.  radialis),  supplies  all  the 
muscles  of  the  radial  side  and  back  of  the  arm,  except  3,  also  the  liga- 
ments and  articulations  of  the  carpus. 

TABLE   OF  THE   CORDS   OF  THE   BRACHIAL   PLEXUS 

Outer  or  Lateral  Cord  (superior) 

Musculo-cutaneous  (n.  musculotaneus) .  derivation  5,  6,  C. 

External  (lateral)  Anterior  Thoracic derivation  5,  6,  7,  C. 

Outer  (lateral)  head  of  Median 'derivation  6,  7,  C. 

Inner  or  Medial  Cord  (inferior) 

Inner  (medial)  head  of  median derivation  8,  C.  i,  T. 

Internal  (medial)  Anterior  Thoracic..  .  .derivation  8,  C.  i,  T. 
Internal  Cutaneous  (n.  cutaneus  anti- 

brachii  medialis) derivation  8,  C.  i,  T. 

Lesser  Internal  Cutaneous  (n.  cutaneus 

brachii  medialis) derivation  i,  T. 

Ulnar derivation  8,  C.  i,  T. 


THE   SPINAL  NERVES  231 

Posterior  Cord 

Upper  Subscapular derivation  5,  6,  C. 

Long  Subscapular  (n.  thoraco-dorsalis). derivation  5,  6,  7,  C. 

Lower  Subscapular derivation  5,  6,  C. 

Circumflex  (n.  axillaris) derivation  5,  6,  C. 

Musculo-Spiral  (n.  radialis) derivation   5,6, 7,8.C.  (i,  7\). 

THE  THORACIC  NERVES  (NERVI  THORACALES) 

The  Thoracic  Nerves  (Plate  12)  are  12  in  number  on  each  side.  Their 
posterior  divisions  pass  backward  beneath  the  transverse  processes,  and 
divide  into  internal  and  external  branches,  supplying  the  muscles  and  in- 
tegument of  the  back.  Their  anterior  divisions,  the  intercostal  nerves,  are 
distributed  to  the  walls  of  the  thorax  and  abdomen,  separately  from  each 
other,  without  plexiform  arrangement.  The  upper  6,  except  the  ist  and 
the  intercosto-humeral  (intercosto-brachial)  branch  of  the  2d,  are  lim- 
ited in  their  distribution  to  the  parietes  of  the  chest.  The  lower  6  supply 
the  walls  of  the  chest  and  abdomen,  the  last  one  sending  a  cutaneous  fila- 
ment to  the  buttock.  The  Lateral  Cutaneous  nerves  are  derived  from  the 
intercostals,  midway  between  the  vertebrae  and  the  sternum;  they  pierce 
the  external  intercostal  and  serratus  magnus  (m.  serratus  anterior)  mus- 
cles, and  divide  into  anterior  and  posterior  branches.  Peculiar  among  the 
thoracic  nerves  and  their  branches  are  the — 
First  Thoracic, — divides  into  2  branches,  one  entering  into  the  brachial 

plexus,  the  other  forming  the  ist  intercostal  nerve. 

Intercosto-humeral  (n.  Intercostobrachialis), — is  the  lateral  cutaneous 
branch  of  the  2d  intercostal  (anterior  division  of  the  2d  thoracic);  it 
pierces  the  external  intercostal  muscle  and  crosses  the  axilla,  joining 
with  a  filament  from  the  lesser  internal  cutaneous  (n.  cutaneus 
brachii  medialis)  (nerve  of  Wrisberg),  supplying  the  skin  of  the  upper 
half  of  the  inside  and  back  of  the  arm,  and  communicating  with  the 
internal  cutaneous  (n.  cutaneus  brachii  posterior)  branch  of  the  mus- 
culo-spiral  nerve  (n.  radialis). 

Last  Thoracic, — is  larger  than  the  other  thoracic  nerves.  Its  anterior 
division  runs  along  the  lower  border  of  the  last  rib,  and  communicates 
with  the  first  lumbar  nerve  by  the  thoraco-lumbar  branch,  also  with 
the  ilio-hypogastric  branch  of  the  lumbar  plexus.  One  of  its 
branches,  the — 

Lateral  Cutaneous- of  the  i2th  Thoracic, — is  also  of  large  size,  and  is  dis- 
tributed to  the  integument  over  the  front  part  of  the  gluteal  region, 
some  of  its  filaments  extending  as  low  as  the  trochanter  major  of  the 
femur. 


232  HUMAN    ANATOMY 

THE  LUMBAR  NERVES 

The  Lumbar  Nerves  are  5  in  number  on  each  side.  Their  roots  are  large 
and  descend  vertically  in  the  spinal  canal  to  reach  their  respective  inter- 
vertebral  foramina  of  exit.  Their  posterior  divisions  pass  backward 
between  the  transverse  processes,  and  divide  into  internal  (medial) 
branches,  supplying  the  deep  muscles  of  the  back;  and  external  (lateral) 
branches  are  mostly  cutaneous.  Their  anterior  divisions  pass  outwardly 
behind  the  psoas  magnus  muscle  or  between  its  fasciculi.  The  anterior 
divisions  of  the  upper  4  nerves  are  connected  by  anastomotic  loops,  form- 
ing the  lumbar  plexus;  that  of  the  5th  with  a  branch  of  the  4th  forms  the 
lumbo-sacral  cord  (truncus  lumbosacralis),  which  joins  with  the  anterior 
divisions  of  the  upper  3  sacral  nerves  and  part  of  the  4th  to  form  the  sacral 
plexus.  (See  Plate  14.) 

The  Lumbar  Plexus  (plexus  lumbalis)  (Plate  14),  is  formed  by  loops 
from  the  1 2th  thoracic  and  the  upper  4  lumbar  nerves.  It  is  situated  in  the 
substance  of  the  psoas  magnus  muscle  in  front  of  the  transverse  processes 
of  the  lumbar  vertebrae.  Its  branches  are  given  off  by  the  connecting 
loops,  and  are  as  follows: — 

Ilio-hypo gastric, — from  the  ist  lumbar  nerve,  to  the  integument  of  the 
gluteal  and  hypogastric  regions. 

Ilio-inguinal, — from  the  ist  lumbar  nerve,  gives  off  muscular  branches 
to  the  internal  oblique  as  it  pierces  it.  It  then  accompanies  the 
spermatic  cord,  or  round  ligament,  divides  into  anterior  scrotal  or 
anterior  labial  to  the  integument  of  the  upper  and  inner  thigh  and  to 
the  scrotum  or  labium  majus. 

Genito-crural  (genito-f emoral) , — from  the  ist  and  26.  lumbar  nerves, 
gives  off  genital  branch  (n.  spermaticus  externus),  to  the  cremaster 
muscle  or  round  ligament,  and  a  femoral  branch  (n.  lumbo-inguinalis) 
to  the  integument  over  the  anterior  superior  part  of  the  thigh. 

External  Cutaneous  (n.  cutaneus  femoris  lateralis), — from  the  2nd  and 
3rd  lumbar  nerves,  to  the  integument  of  the  anterior,  outer  and  pos- 
terior parts  of  the  thigh. 

Obturator  (n.  obturatorius), — from  the  2nd,  3rd,  and  4th  lumbar  nerves, 
through  the  obturator  foramen,  to  the  obturator  externus  and  adduc- 
tor muscles  of  the  thigh,  the  hip-  and  knee-joints,  and  occasionally  the 
integument  of  the  thigh  and  leg. 

Accessory  Obturator  (n.  obturatorius  accessorius)  (often  absent), — from 
the  3rd  and  4th  lumbar  nerves,  to  the  pectineus  muscle  and  the 
hip-joint. 


THE    SPINAL    NERVES  233 

Anterior   Crural  (n.  femoralis), — from  the  2nd,  3rd,  and  4th  lumbar 
nerves,  to  the  iliacus  and  pectineus  muscles,  all  the  muscles  on  the 
front  of  the  thigh  except  the  tensor  fasciae  femoris,  the  hip-  and  knee- 
joints,  and  the  integument  on  the  front  and  inner  side  of  the  thigh.     It 
descends  through  the  psoas  magnus  muscle,  passing  beneath  Pou- 
part's  inguinal  ligament  to  the  thigh,  where  it  divides  into  an  interior 
and  a  posterior  division.     Its  branches  are — 
Muscular,  within  the  abdomen,  to  the  iliacus  muscle. 
Arterial,  within  the  abdomen,  to  the  femoral  artery. 
Middle  Cutaneous,  to  the  skin  on  the  front  of  the  thigh. 
Internal  Cutaneous,  to  the  skin  on  the  knee  and  leg. 
Muscular,  to  the  pectineus  and  sartorius  muscles. 
Long  Saphenous  (n.  saphenus),  to  the  skin  over  the  patella  and  that  on 

the  front  and  inner  side  of  the  leg. 
Muscular,  to  the  quadriceps  extensor  muscle. 
Articular  Branches,  to  the  hip-  and  knee-joints. 

THE  SACRAL  AND  COCCYGEAL  NERVES 

The  Sacral  Nerves  number  5,  the  Coccygeal  i,  on  each  side.  Their  roots 
are  long  and  descend  vertically  in  the  spinal  canal  as  the  cauda  equina  or 
horse's  tail,  to  reach  their  respective  foramina  of  exit.  Their  posterior  divi- 
sions are  small;  they  supply  the  multifidus  spinae  muscles  and  the  skin  of 
the  gluteal  region;  those  of  the  lower  2  sacral  and  the  coccygeal  supplying 
the  extensor  coccygis  and  the  skin  over  the  coccyx.  Their  anterior  divisions 
communicate  with  the  sacral  ganglia  of  the  sympathetic;  those  of  the  3 
upper  sacral,  with  the  lumbo-sacral  cord  (truncus  lumbo-sacralis)  and  a 
branch  from  the  4th  sacral,  unite  to  form  the  sacral  plexus.  The  anterior 
division  of  the  4th  sacral  divides  into  visceral  and  muscular  branches,  the 
former  supplying  the  pelvic  viscera,  the  latter  the  levator  ani,  sphincter 
ani,  and  coccygeus  muscles.  The  anterior  division  of  the  5th  sacral  and 
the  coccygeal  supply  the  coccygeus  muscle  and  the  skin  over  the  coccyx. 

The  Sacral  Plexus  (Plexus  Sacralis)  (Plate  14), — is  formed  by  the  union 
of  the  anterior  divisions  of  the  upper  3  and  part  of  the  4th  sacral  nerves  (c), 
with  the  lumbo-sacral  cord  (truncus  lumbo-sacralis)  (a)  derived  from  the 
4th  and  5th  lumbar  nerves.  The  plexus  lies  upon  the  pyriformis  muscle,  is 
covered  by  the  pelvic  fascia,  communicates  with  the  sympathetic,  and 
gives  off  2  great  nerve-trunks  or  cords,  the  upper  cord  being  prolonged  as  the 
great  sciatic  nerve,  the  lower  cord  becoming  the  pudic  nerve,  both  passing 
out  of  the  pelvis  by  the  great  sacro-sciatic  foramen.  The  branches  of  the 
sacral  plexus  are  as  follows: — 


234 


HUMAN   ANA10MY 


FIG.  80. 


Muscular  Branches, — to  the  pyriformis,  obturator  interims,  the  2  gemelli 

and  the  quadratus  femoris. 

Superior  Gluleal  (n.  glutaeus  superior)  (b), — from  the  lumbo-sacral  cord, 
to  the  gluteus  medius  and  minimus  muscles 
and  the  tensor  fasciae  femoris. 

Inferior  Gluleal  (n.  glutaeus  inferior), — from  the 
lumbo-sacral  cord  and  the  ist  and  26.  sacral 
nerves,  to  the  gluteus  (glutaeus)  maximus  muscle. 
Small  Sciatic  (n.  cutaneus  femoris  posterior)  (/), — 
from  the  2d  and  3d  sacral  nerves,  to  the  integu- 
ment of  the  perineum  and  back  part  of  the  thigh 
and  leg,  by  gluteal,  perineal  and  femoral  cuta- 
neous branches. 

Perforating  Cutaneous  (n.  clunium  inferior  medialis), 
sometimes  classed  as  a  branch  of  the  "pudendal 
plexus," — from  the  2d  and  3d  sacral  nerves, 
perforating  the  great  sacro-sciatic  (sacro-tu- 
berous)  ligament,  to  the  skin  over  the  gluteus 
maximus  muscle. 

Pudic  (n.  pudendus),  sometimes  classed  as  a  branch 
of  the  "pudendal  plexus"  (e),— from  the  3d  and 
4th  sacral  nerves,  escapes  by  the  great  sacro- 
sciatic  foramen,  crosses  the  spine  of  theischium, 
and  re-enters  the  pelvis  through  the  lesser  sacro- 
sciatic  foramen,  to  supply  the  perineum,  anus 
and  genitalia.  Its  branches  are  the — 

Inf.  Hemorrhoidal  (n.  haemorrhoidalis  inferior). 
Perineal    (n.   perinei),   dividing  into  2  super- 
ficial perineal  cutaneous  branches  and  mus- 
cular branches  to  all  of  the  perineal  muscles. 
Dorsal  Nerve  of  the  Penis  (n.  dorsalis  penis  vel 

clitoridis). 

Great  Sciatic  (n.  ischiadicus)  (g), — the  largest  ner- 
vous cord  in  the  body,  and  the  continuation  of 
the  upper  cord  of  the  sacral  plexus,  arises  from 
the  lumbo-sacral  cord  and  the  upper  4  sacral 
nerves,  and  escapes  by  the  great  sacro-sciatic 
foramen  to  the  back  of  the  thigh,  giving  off — 

Articular  Branches  (rami  articulares),  to  the  hip-joint. 

Muscular  Branches  (rami  musculares),  to  the  flexor  muscles  of  the 


THE    SPINAL    NERVES  235 

leg,  viz. — the  biceps,  semitendinosus  and  semimembranosus,  also 
to  the  adductor  magnus. 

External  (n.  peronaeus  communis)  (K)  and  Internal  (n.  tibialis)  (i) 
Popliteal,  the  terminal  branches,  generally  arising  at  the  lower 
third  of  the  thigh. 

The  Internal  Popliteal  Nerve  (n.  tibialis)  (i),  the  larger  of  the  two  ter- 
minal branches  of  the  great  sciatic,  descends  along  the  back  of  the  lower 
thigh  and  the  middle  of  the  popliteal  space,  to  the  lower  part  of  the 
popliteus  muscle,  where  it  becomes  the  Posterior  Tibial  Nerve  (&).  Its 
branches  are  the — 

Articular  (rami  articulares)  3, — supplying  the  knee-joint. 

Muscular  (rami  musculares)  (j),  4  or  5, — to  the  gastrocnemius,  plantaris, 

soleus  and  popliteal  muscles. 
Communicant  Tibialis  (ramus  anastomoticus  tibialis), — joins  the  com- 

municans  peronei  from  the  external  popliteal  nerve  to  form  the — 
External  or  Short  Saphenous  (n.  cutaneus  surae  medialis)  (/»), — descends 
to  the  outer  malleolus  and  is  distributed  to  the  skin  of  the  outer  side  of 
the  foot  and  the  little  toe. 

The  Posterior  Tibial  Nerve  (&),  the  continuation  of  the  internal  popliteal 
descends  along  the  back  of  the  leg  to  behind  the  inner  malleolus,  where  it 
divides  into  the  External  (lateral)  and  Internal  (medial)  Plantar  nerves  (/). 
Its  branches  are  the — 

Muscular    (rami    musculares), — to  the  soleus,  tibialis  posticus,  flexor 

longus  digitorum  and  flexor  longus  hallucis. 
Calcaneo- plantar  or  Internal  Calcaneal  (rami  calcanei  mediales), — to  the 

skin  of  the  heel  and  inner  side  of  the  sole  of  the  foot. 
Articular   (ramus  articularis  ad  articulationem  talocrualem), — to  the 

ankle-joint. 

Internal  Plantar  (n.  plantaris  medialis), — to  the  inner  plantar  muscles, 
sole  of  the  foot,  and  the  plantar  integument  of  the  inner  3^  toes  (nn. 
digi tales  plantares  communes). 

External  Plantar  (n.  plantaris  lateralis), — to  the  external  plantar  mus- 
cles, and  the  plantar  integument  of  the  outer  ij^j  toes  (nn.  digitales 
plantares  communes). 

The  External  Popliteal  or  Peroneal  Nerve  (n.  peronaeus  communis)  (h), 
the  smaller  of  the  two  terminal  branches  of  the  great  sciatic  (n.  ischiadicus), 
descends  from  the  bifurcation  of  the  latter  nerve,  obliquely  along  the  outer 
side  of  the  popliteal  space,  winds  around  the  neck  of  the  fibula,  and  about 
an  inch  below  the  head  of  that  bone  it  divides  into  the  Anterior  Tibial 
or  Deep  Peroneal  (n.  peronaeus  profundus)  (m)  and  Musculo-cutaneous  or 


236  HUMAN   ANATOMY 

Superficial  Peroneal  (n.  peronaeus  superficialis)  (n)  nerves.  Its  branches 
are — 

Articular  (rami  articulares),  3, — to  the  front  and  outer  side  of  the  knee. 

Cutaneous  (n.  cutaneus  surae  lateralis),  2  or  3, — to  the  integument  along 
the  back  and  outer  side  of  the  leg.  One  of  these  branches,  the — 

Communicant  Peronei  (ramus  anastomoticus  peronaeus), — joins  with  the 
communicans  tibialis  (ramus  anastomoticus  tibialis)  (see  above) 
to  form  the  external  saphenous  nerve  (n.  cutaneus  surae  medialis). 

Anterior  Tibial  or  Deep  Peroneal  (n.  peronaeus  profundus)  (m), — sup- 
plying the  extensor  muscles,  the  ankle-joint,  and  the  integument  of 
the  adjacent  sides  of  the  great  and  26.  toes. 

Musculo-cutaneous  or  Superficial  Peroneal  (n.  peronaeus  superficialis) 
(n), — by  2  branches  (0)  (internal  and  external)  to  the  peroneal 
muscles,  the  integument  of  the  ankles,  and  the  dorsal  integument 
(n.  cutaneous  dorsalis  medialis)  and  sides  of  all  the  toes,  except  the 
outer  side  of  the  little  toe  and  the  adjoining  sides  of  the  great  and  2d 
toes,  the  former  being  supplied  by  the  external  saphenous  (n.  cuta- 
neus surae  medialis),  and  the  latter  by  the  internal  (medial)  branch  of 
the  anterior  tibial. 

THE     SYMPATHETIC  SYSTEM 

The  Sympathetic  Nervous  System  consists  of — a  series  of  ganglia, 
connected  together  by  intervening  cords,  one  series  on  each  side  of  the 
median  line  of  the  body,  partly  in  front  and  partly  on  each  side  of  the 
vertebral  column,  beginning  in  the  ganglion  of  Ribes  on  the  anterior  com- 
municating artery  and  ending  in  the  ganglion  impar  in  front  of  the  coccyx; 
three  great  gangliated  plexuses,  situated  in  the  thoracic,  abdominal,  and 
pelvic  cavities  respectively;  smaller  ganglia,  in  relation  with  the  abdominal 
viscera;  and  numerous  communicating  and  distributing  nerve  fibres. 
(See  Plate  16.) 

Ganglia  in  the  Cranium.  Besides  the  ganglia  of  the  cranial  nerves 
(described  on  page  223),  all  of  which  are  connected  with  the  sympathetic, 
there  are  in  the  cranium  or  in  its  immediate  vicinity  certain  ganglia  belong- 
ing to  the  sympathetic  system,  as  follows: — 

Carotid  Ganglion, — on  the  internal  carotid  artery. 

Ganglion  of  Bochdalek, — above  the  canine  tooth  at  the  junction  of  a 
branch  from  the  spheno-palatine  ganglion  with  the  middle  superior 
alveolar  and  anterior  superior  alveolar  nerves. 

Ganglion  of  Valent ine,  —situated  at  the  juncture  of  the  middle  superior 
alveolar  and  the  posterior  superior  alveolar  nerves. 


THE    SYMPATHETIC    SYSTEM  237 

The  Carotid  Plexus  is  situated  on  the  outer  side  of  the  internal  carotid 
artery,  as  it  lies  by  the  side  of  the  body  of  the  sphenoid  bone,  and  is  formed 
by  filaments  from  the  outer  branch  of  the  superior  cervical  ganglion.  It 
communicates  with  the  Gasserian  ganglion  (ganglion  semilunare)  and  the 
6th  nerve;  also  with  the  tympanic  branch  of  the  gth  by  two  branches,  the 
small  deep  petrosal  and  the  carotko-tympanic;  and  with  the  spheno-pala- 
tine  ganglion  by  the  large  deep  petrosal,  which  joins  the  great  superficial 
petrosal  to  form  the  Vidian  nerve  (n.  canalis  pterygoidei)  before  entering 
the  ganglion  (see  page  226). 

The  Cavernous  Plexus  is  situated  in  the  upper  portion  of  the  cavernous 
sinus,  below  the  last  bend  of  the  internal  carotid  artery,  and  is  formed 
chiefly  by  the  internal  division  of  the  ascending  branch  from  the  superior 
cervical  ganglion.  It  communicates  with  the  3rd,  4th,  ophthalmic  divi- 
sion of  the  $th,  and  the  6th  nerves,  also  with  the  ophthalmic  ganglion.  It 
sends  filaments  to  the  wall  of  the  internal  carotid  artery,  which  are  pro- 
longed into  plexuses  around  the  cerebral  and  ophthalmic  arteries.  The 
filaments  on  the  anterior  communicating  artery  form  the  ganglion  of  Ribes, 
which  here  connects  the  sympathetic  of  the  two  sides  of  the  body. 

«tf    THE  GANGLIATED  CORD  (TRUNCUS  SYMPATHETICUS) 
"      ' 

The  Cervical  Ganglia  are  3  in  number  on  each  side  of  the  neck,  the  supe- 
rior, middle  and  inferior  cervical;  of  which  the  superior  is  the  largest  and  is 
probably  formed  by  the  coalescence  of  four  ganglia  corresponding  to  the 
upper  four  cervical  nerves.     They  are  as  follows: — 
Superior  Cervical  Ganglion, — of  fusiform  shape,  situated  behind  the 
carotid  sheath  opposite  the  transverse  processes  of  the  2d  and  3d 
cervical  vertebrae.     Its  branches  form  the  carotid,  cavernous,  and 
pharyngeal  plexuses;  one  of  its  internal  branches  unites  with  the 
superior  laryngeal  nerve,  and  another  is  the  superior  cervical  cardiac 
nerve  going  to  the  cardiac  plexuses. 

Middle  Cervical  Ganglion, — on  the  inferior  thyroid  artery,  opposite  the 
6th  cervical  vertebra  gives  off  the  middle  cardiac  nerve  to  the  deep 
cardiac  plexus,  also  many  communicating  branches. 
Inferior  Cervical  Ganglion, — on  the  superior  intercostal  artery,  between 
the  neck  of  the  ist  rib  and  the  transverse  process  of  the  7th  cervical 
vertebra.  It  gives  off  several  communicating  branches  and  the 
inferior  cardiac  nerve  to  the  deep  cardiac  plexus. 

The  Thoracic  Ganglia  are  1 1  or  1 2  in  number  on  each  side  of  the  spine, 
resting  against  the  heads  of  the  ribs  and  covered  by  the  pleura  costalis, 


238  HUMAN   ANATOMY 

except  the  last  two,  which  are  placed  on  the  side  of  the  bodies  of  the  nth 
and  1 2th  thoracic  vertebrae.     Occasionally  two  ganglia  coalesce  into  one, 
and  the  first  is  frequently  blended  with  the  last  cervical  ganglion.     They 
are  connected  together  by  cords  prolonged  from  their  substance.     They 
receive  branches  (white  rami  communicantes)  from  the  thoracic  nerves. 
They  give  off  central  branches  (gray  rami  communicantes)  connecting  with 
the  thoracic  spinal  nerves;  and  peripheral  branches  from  the  upper  5  or  6 
ganglia  to  the  thoracic  aorta,  etc.,  from  the  3rd  and  4th  ganglia  to  the 
posterior  pulmonary  plexus,  and  from  the  lower  6  or  7  ganglia  to  form  by 
their  union  the  three  splanchnic  nerves,  as  follows: — 
Great  Splanchnic, — from  branches  of  the  5th  to  the  loth  inclusive,  con- 
necting with  the  upper  5,  passes  through  the  posterior  mediastinum, 
perforates  the  crus  of  the  diaphragm,  to  the  semilunar   (coeliac) 
ganglion  of  the  solar  (cceliac)  plexus. 

Lesser  Splanchnic, — from  the  loth  and  nth,  passes  through  the  dia- 
phragm with  the  great  splanchnic,  to  the  renal  and  solar  (cceliac) 
plexuses. 

Least  or  Renal  Splanchnic, — from  the  last  thoracic  ganglion,  also  per- 
forates the  diaphragm,  and  ends  in  the  renal  plexus;  it  is  not  always 
present. 

The  Lumbar  Ganglia  consist  usually  of  4  small  ganglia  on  each  side, 
connected  together  by  intervening  cords,  and  situated  in  front  of  the  ver- 
tebral column.  Their  central  branches  (gray  rami  communicantes)  com- 
municate with  the  lumbar  spinal  nerves.  Of  their  peripheral  branches 
some  help  to  form  the  aortic  plexus,  others  go  to  the  hypogastric  plexus, 
and  all  give  off  numerous  filaments  to  the  bodies  of  the  lumbar  vertebrae 
and  the  ligaments  connecting  them.  The  lumbar  ganglia  receive  branches 
(white  rami  communicantes)  from  the  ist,  2d  and  sometimes  3d  lumbar 
nerves. 

The  Pelvic  Ganglia  are  4  or  5  small  ganglia  on  each  side,  connected  to- 
gether by  intervening  cords,  and  situated  in  front  of  the  sacrum.  The 
lower  cords  of  each  side  converge  below  and  unite  on  the  front  of  the  coccyx 
in  the  coccygeal  ganglion  or  ganglion  coccygeum  impar.  Their  central 
branches  (gray  rami  communicantes),  2  from  each  ganglion,  communicate 
with  the  sacral  nerves.  Of  the  peripheral  branches,  some  pass  to  the  pelvic 
plexus,  others  go  to  a  plexus  on  the  middle  sacral  artery  and  all  communi- 
cate on  the  front  of  the  sacrum  with  the  corresponding  branches  of  the 
other  side.  The  sacral  portion  of  the  sympathetic  trunk  receives  one  with 
rami  communicantes. 


THE    SYMPATHETIC   SYSTEM  239 

THE  GREAT  PLEXUSES  (Plate  16) 

The  Great  Plexuses  of  the  Sympathetic  are  large  aggregations  of  nerves 
and  ganglia,  situated  in  the  tkpracic,  abdominal,  and  pelvic  cavities,  and 
named  the  Cardiac  Plexus,  the  Coeliac  or  Solar  Plexus,  and  the  Hypo- 
gastric  Plexus.  Their  branches  form  secondary  plexuses  which  supply  the 
viscera  of  the  cavities,  as  described  below. 

The  Cardiac  Plexus  is  situated  at  the  Jjase  of  the  heart,  and  is  divided 
into  a  superficial  portion  and  a  deep  portion,  both  of  which  are  closely  con- 
nected with  each  other.  They  form  by  their  branches  the  anterior  and 
posterior  coronary  plexuses  and  the  anterior  pulmonary  plexus. 

The  Superficial  Cardiac  Plexus  is  formed  by  the  left  superior  cardiac 
nerve,  the  left  inferior  cervical  cardiac  branches  of  the  pneumogastric,  and 
filaments  from  the  deep  cardiac  plexus.  At  the  junction  of  these  nerves  a 
small  ganglion,  the  cardiac  ganglion  of  Wrisberg,  is  occasionally  found,  situ- 
ated immediately  beneath  the  arch  of  the  aorta  on  the  right  side  of  the 
ductus  arteriosus  (ligamentum  arteriosum).  This  plexus  lies  in  the  con- 
cavity of  the  arch  of  the  aorta,  and  in  front  of  the  right  pulmonary  artery. 
Branches  from  it  pass  to  the — 

i  Right  Anterior  Coronary  Plexus, — formed  chiefly  from  the  preceding, 
also  from  the  deep  cardiac  plexus.  It  passes  forward  between  the 
aorta  and  the  pulmonary  artery.  It  follows  the  ramifications  of  the 
right  coronary  artery  on  the  anterior  surface  of  the  heart. 
Right  and  Left  Anterior  Pulmonary  Plexuses, — are  formed  by  filaments 
from  the  superficial  and  deep  cardiac  plexuses  and  the  anterior  pul- 
monary branches  of  the  vagus  nerve.  Branches  from  them  accompany 
the  ramifications  of  the  bronchial  tubes  throughout  the  lungs.  The 
Right  and  Left  Posterior  Pulmonary  Plexuses  are  formed  by  the  pos- 
terior pulmonary  branches  of  the  vagus  and  branches  from  the  3rd 
and  4th  thoracic  ganglia  of  the  sympathetic.  They  are  not  con- 
nected with  the  cardiac  plexuses.  They  are  situated  on  the  pos- 
terior aspect  of  the  roots  of  the  lungs,  and  their  branches  accompany 
the  ramifications  of  the  bronchial  tubes. 

The  Deep  Cardiac  Plexus  is  formed  by  the  cardiac  nerves  derived 
from  the  cervical  ganglia  of  the  sympathetic  and  the  cardiac  branches  of 
the  recurrent  laryngeal  and  pneumogastric  nerves.  The  only  cardiac 
nerves  which  do  not  enter  into  its  formation  are  those  forming  the  super- 
Seta!  cardiac  plexus,  namely — the  left  superior  cardiac  and  the  inferior 
.  cervical  cardiac  branches  of  the  vagus.  This  plexus  lies  in  front  of  the 
bifurcation  of  the  trachea  and  behind  the  arch  of  the  aorta.  Its  branches 


240  HUMAN   ANATOMY 

on  the  right  side  pass  in  front  and  behind  the  right  pulmonary  artery 
to  the  anterior  pulmonary  plexuses,  the  anterior  (right)  and  posterior 
(left)  coronary  plexuses,  and  the  right  auricle;  those  on  the  left  side  give 
filaments  to  the  superficial  cardiac  and  anterior  pulmonary  plexuses  and 
the  left  auricle,  and  then  form  the  greater  part  of  the — 

Left  or  Posterior  Coronary  Plexus, — is  formed  by  filaments  from  both 
sides  of  the  deep  cardiac  plexus.  It  surrounds  the  branches  of  the 
left  coronary  artery  at  the  back  of  the  heart,  and  its  filaments  are 
distributed  with  those  vessels  to  the  muscular  substance  of  the 
ventricles. 
Ganglia, — are  found  on  the  cardiac  nerves,  both  on  the  surface  of  the 

heart  and  in  its  muscular  substance. 

'  The  Epigastric  (Cceliac)  or  Solar  Plexus,  sometimes  called  the  abdomi nal 
brain,  consists  of  a  great  network  of  nerves  and  ganglia,  situated  behind 
the  stomach  and  in.  front  of  the  aorta  and  the  crura  of  the  diaphragm, 
surrounding  the  cceliac  axis  and  the  root  of  the  superior  mesenteric  artery. 
Its  principal  ganglia  are  the  two  Semilunar  (coeliac)  Ganglia,  irregular 
gangliform  masses,  formed  by  the  aggregation  of  smaller  ganglia  with 
interspaces  between  them,  situated  one  on  each  side  of  the  plexus,  and 
in  front  of  the  crura  of  the  diaphragm,  close  to  the  supra-renal  capsules. 
This  plexus  and  its  connected  ganglia  receive  the  great  and  small  splanch- 
jiic  nerves  of  both  sides,  and  some  filaments  from  the  right  pneumogastric. 
It  distributes  filaments  over  all  the  branches  from  the  front  of  the 
abdominal  aorta,  forming  the  following  plexuses: — 

/  Phrenic  or  Diaphragmatic  Plexus, — arises  from  the  upper  part  of  the 
semilunar  ganglion,  and  receives  one  or  two  branches  from  the  phrenic 
nerve.  It  accompanies  the  phrenic  artery  and  supplies  the  dia- 
phragm, some  filaments  going  to  the  supra-renal  capsule.  At  its 
junction  with  the  phrenic  nerve  on  the  right  side  is  the — 
Ganglion  Diaphragmaticum, — a  small  ganglion  at  the  juncture  with 
the  right  phrenic  nerve,  it  is  situated  on  the  under  surface  of  the 
diaphragm,  near  the  right  supra-renal  capsule. 

.  Supra-renal  Plexus, — is  formed  by  branches  from  the  solar  plexus,  the 
semilunar  ganglion,  the  phrenic  and  great  splanchnic  nerves.  Its 
branches  are  large,  and  supply  the  supra-renal  capsule. 
Renal  Plexus, — is  formed  by  filaments  from  the  solar  plexus,  the  serai- 
lunar  ganglion,  the  aortic  plexus,  and  the  lesser  and  smallest  splanch- 
nic nerves,  some  15  or  20  in  all,  which  have  numerous  ganglia 
on  them.  They  accompany  the  branches  of  the  renal  artery  into  the 
kidney,  some  filaments  going  to  the  inferior  vena  cava  and  to  the 
spermatic  plexus. 


THE    SYMPATHETIC    SYSTEM  241 

Spermatic  Plexus— is  derived  from  the  renal  plexus  and  receives  fila- 
ments from  the  aortic  plexus.  It  accompanies  the  spermatic  vessels 
to  the  testes.  In  the  female  it  is  called  the  Ovarian  Plexus,  and  is 
distributed  to  the  ovaries  and  the  fundus  of  the  uterus. 

Superior  Gastric  or  Coronary  Plexus, — joins  with  branches  from  the 
left  pneumogastric  nerve,  and  accompanies  the  gastric  left  artery  along 
the  lesser  curvature  of  the  stomach,  being  distributed  to  that  viscus. 

Hepatic  Plexus, — receives  filaments  from  the  left  pneumogastric  and 
the  right  phrenic  nerves,  accompanies  the  hepatic  artery,  and  ramifies 
in  the  substance  of  the  liver  upon  the  branches  of  that  artery  and  those 
of  the  portal  vein.  It  gives  off  branches  to  all  the  divisions  of  the 
hepatic  artery,  forming  pyloric,  gastro-duodenal,  gastro-epiploic 
(inferior  gastric),  and  cystic  plexuses,  on  the  arteries  similarly  named. 

/Splenic  or  Lienal  Plexus, — is  formed  by  branches  from  the  cceliac  plexus, 
the  left  semilunar  ganglion,  and  the  right  pneumogastric  nerve. 
It  accompanies  the  splenic  artery  and  its  branches  to  the  substance 
of  the  spleen,  and  gives  off  filaments  to  the  pancreas  and  the  left 
gastro-epiploic  plexus. 

Superior  Mesenteric  Plexus, — is  a  continuation  of  the  solar  plexus,  and 
receives  a  branch  from  the  right  pneumogastric  nerve.  It  surrounds 
the  superior  mesenteric  artery,  and  divides  into  pancreatic,  intes- 
tinal, ileo-colic,  right  colic,  and  middle  colic  branches,  which  are 
distributed  to  all  the  parts  supplied  by  that  artery.  Its  nerves  have 
numerous  ganglia  upon  them  near  their  origin. 

Aortic  Plexus, — on  the  sides  and  front  of  the  aorta,  between  the  origins 
of  the  superior  and  inferior  mesenteric  arteries;  is  formed  by  branches 
from  the  solar  (cceliac)  plexus  and  semilunar  (cceliac)  ganglia,  and 
receives  filaments  from  the  lumbar  ganglia.  It  sends  branches  to 
the  spermatic,  inferior  mesenteric,  and  hypogastric  plexuses,  also 
some  filaments  to  the  inferior  vena  cava.  A  part  of  it  is  the — 

Inferior  Mesenteric  Plexus, — divides  into  left  colic,  sigmoid,  and  superior 
haemorrhoidal  plexuses,  and  supplies  the  descending  colon  and  the 
rectum. 

The  Hypogastric  Plexus  is  formed  by  filaments  from  the  aortic  plexus 
and  the  lumbar  ganglia,  and  is  situated  in  front  of  the  promontory  of  the 
sacrum  between  the  two  common  iliac  arteries.  It  contains  no  evident 
ganglia,  and  bifurcates  into  two  lateral  divisions,  the  Pelvic  or  Inferior 
Hypogastric  Plexuses,  one  on  ea,ch  side  of  the  rectum,  which  receive  branches 
from  the  2nd,  3rd,  and  4th  sacral  nerves,  and  the  first  two  sacral  ganglia. 
They  give  off  numerous  branches  along  the  branches  of  the  internal  iliac 
16 


242  HUMAN   ANATOMY 

arteries  to  the  pelvic  viscera,  forming  the  following  secondary  plexuses, 
viz. — 

Inferior  Hamorrhoidal  Plexus, — to  the  rectum. 

Vesical  Plexus, — to  the  bladder,  vesiculae  seminales,  and  vas  deferens. 
Prostatic  Plexus, — to  that  gland  and  the  vesiculae  seminales,  also  to  the 

erectile  tissue  of  the  penis  as  the  large  and  small  cavernous  nerves. 
Vaginal  Plexus, — to  the  vagina,  gives  off  anteriorly  the  cavernous  plexus 

of  the  clitoris  from  which  arise  the  greater  and  lesser  cavernous 

nerves  of  the  clitoris. 
Uterine  Plexus, — to  the  uterus  and  Fallopian  tube. 


TABLES  AND  PLATES 

OF   THE 

NERVOUS  SYSTEM 


NOTE. — The  folio-wing  Tables  are  of  original  arrangement,  and  are  designed  to 
show  the  origin,  formation  and  distribution  of  each  nerve.  They  are  self-explana- 
tory with  the  aid  of  the  accompanying  Plates. 


244 


HUMAN  ANATOMY 


THE  CRANIAL  NERVES 

I  Ethmoidal     foramina,     20, 

ist  NERVE, — Olfactory.     Function, — smell.     Exit, —  •<       in    cribriform    plate    of 
(See  page  216)  [      Ethmoid  bone. 


Ext.  Root,  Posterior  division  of  the  Rhin-  | 

encephalon  or  "Limbic  lobe."  istN. 

Mid.  Root,  Optic  thalamus.  [    and 

Int.  Root,  Posterior  division  of  the  Rhin-  |  Bulb. 

encephalon  or  "Limbic  lobe." 


Ext.  Filaments,  to  Schneiderian 
membrane  over  sup.  turbin- 
al  and  ethmoid  bones. 

Int.  Filaments,  to  Septum 
(upper  third). 


Exit, — Optic  foramen. 


2nd  NERVE, — Optic.  Function, — sight. 

(See  page  217) 

This  table  is  too  long  for  the  width  of  the  page,  and  breaks  at  the  Optic  Commissure, 
which  is  repeated  again  where  the  table  continues  below. 


Optic  thalamus 
Ext.  geniculate 
Corp.  quad.  ant. 

Corp.  quad.  ant.    | 
Optic  thalamus     J 


|  Longitudinal 
Fibres  -j  Decussating 
[  Commissural 

\  Commissural 


Left  Optic  Tract 


(  Longitudinal    J 


OPTIC 

COMMISSURE 
or  CHIASM. 


OPTIC 

COMMISSURE 
or  CHIASM. 


[  Longitudinal,  to  temporal  li  of  retina 

Optic  N.  \  Decussating,  fr.  opp.  tract  to  nasal  Yt  of  ret.  \  L.    Eye. 
[  Inter-retinal,  fr.  opp.  retina  to  retina. 

2d 

f  Inter-retinal,  fr.  opp.  retina  to  retina. 

Optic  N.  \  Decussating,  fr.  opp.  tract  to  nasal  te  of  ret.  }•  R.  Eye. 
[  Longitudinal,  to  temporal  J-i  of  retina. 


3d  NERVE,—  Motor  Oculi. 

(See  page  217) 

Nucleus   in        1 
floor  of  the       1         .  „. 
Aqued.ofSyl.  j       3 
Crus  cerebri.    J 

Function,  —  motion.          Exit,  —  Sphenoidal  fissure. 

fSup.  Branch,  to  Lev.  palp,  sup.,  Rectus  superior. 
.  /  to  Rectus  int.,  Rect.  Inf.,  Inf.  oblique. 
Inf.  Branch  s                         L   '    ...              ' 
(  motor  root  to  Ciliary  Ganglion. 

Supplies  all  the  muscles  of  the  orbit  (except  the  superior  oblique  and  ext.  rectus) ,  also 
the  sphincter  of  the  iris  and  the  ciliary  muscle  through  the  ciliary  ganglion. 


Function, — motion. 


Exit, — Sphenoidal  fissure. 


4th  NERVE,— Trochlear. 
(See  page  217) 

f  to  Sup.  Oblique  on  upper  (orbital)  surface. 
4th  N.    \  Branch  to  Cavernous  Plexus  of  Sympathetic. 
I  Recurrent  Branch,  to  lateral  sinus. 


Aq.  of  Sylvius. 
Crus  cerebri. 


Is  the  smallest  cranial  nerve,  with  the  longest  nerve-course  in  the  cranial  cavity. 


THE  CRANIAL  NERVES 


Plate  6 


longitudinal  Fibres 
Decussating  Fibres 
Conuni&sura/Fibres  _. 
fnter-reiinul  Fibr&r 


PoKerdeL 


245 


246 


HUMAN   ANATOMY 


$th  NERVE, — Trigeminus. 
(See  page  218.) 


Functions,  Sensation,  Motion. 


(i)  OPHTHALMIC 
by  Sphenoidal 
fissure. 

Frontal       < 
Lacrimal,  to 

Supraorbital. 
Supratrochlear. 
gland,  etc. 
Ganglionic. 
Long  Ciliary. 

Nasal. 

Infratrochlear. 

Int.  Nasal. 

Ext.  Nasal. 

Meningeal. 

Origin. 
Nucleus  and 

/->  i'A  t        /  Temporal. 
Orbital,       <  ,, 
[  Malar. 

Locus  Cae- 

Spheno-palatine. 

rul.  in  the 

(2)  MAXILLARY 

Post.  Sup.  Denial. 

medulla 
oblongata 

by  For.  rotund. 

Mid  Sup.  Denial.    \  . 
Ant.  Sup.  Denial.   /  'n  canal- 

for  the 

Palpebral,   } 

Sensory  Root. 

Nuclei  in  floor 
of  4th  Ven- 

5th N. 
Trigeminus 
or  Trifacial. 

Nasal,          >  on  the  face. 
Labial,         J 

Recurrent. 

tricle,  and 

(  Ant.  Br.  * 

Aq.  of  Syl- 

Int.Pterygoid,       j  pQgt   B^. 

vius,  for  the 

Masseteric.  * 

Motor  Root  or 

(  Ant.  Br.  * 

Masticator 

Deep  Temporal      j  pos^  ]}r>« 

Nerve. 

Buccal. 

Ext.  Plerygoid.* 

Br.  to  facial  n. 

(3)    MANDIBU- 
LAR.  (including 
masticator)   by 
For.  Ovale. 

A  uriculo- 
Temporal. 

Br.  to  otic  g. 
Ant.  Auricular. 
to  Meat.  Aud. 
to  articulation. 
Parotid. 

Sup.  Temporal. 

Lingual 

Br.  of  Comm'n. 
Br.  of  Distrib'n. 

Mylo-hyoid.  * 

Inferior 

Dental  Brs. 

Dental. 

Incisive.    \  .        .     . 
A  ,      >  terminal 
Mental.    J 

Motor  Branches  (Masticator  Nerve),  going  to  the  muscles  of  mastication. 


T      r  XT  Plate7 

THE  CRANIAL  NERVES. 

5l.h  Nerve,-Trigeminus. 


iotter.del 


247 


248 


HUMAN   ANATOMY 


7th  NERVE, — Facial,  or  Portio  Dura. 
(See  page  220.) 


Function, — Motion,    Special  Sense  (taste) 


In      auditory  ' 
canal. 

>  Br.  to  Auditory  nerve. 

Large  Superf.  Petrosal,  to  Meckel's 

ganglion. 

. 

Small     Superf.     Petrosal,     to     otic 

.0 

In    Aqueduct 

ganglion. 

1 

of  Fallopius. 

Ext.    Superf.    Petrosal,    to    menin- 

'% 

geal  plex. 

a 

§ 

Br.    to    Auricular    of    pneumogas- 

g 

tric. 

o 

O 

Origin. 
Nucleus  in 
floor  of  the 

•8 
1 

At   exit   from 
the  Stylo- 

Br.     to     Great     Auricular     (cerv. 
plex.). 
Br.  to  Auriculo-Temporal  (sth). 

4th  Ventricle, 
and  groove 

o 

a 

rt 

Foramen. 

Br.  to  Pneumogastric. 
Br.  to  Glosso-pharyngeal. 

between 
Olivary  and 

7th  N. 
Facial 

W 

Behind  the 
ear. 

>  Br.  to  small  Occipital. 

Restiform 

facial 

On  the  face. 

Brs.  to  3  divisions  of  the  sth  nerve. 

bodies  of 

medulla 

In  the  neck. 

Br.  to  Superficial  Cervical. 

oblongata. 

Solitary 

Tympanic     Nerve,      to      Stapedius 

Tract. 

In    Aqueduct  ^ 

muscle. 

e 

of  Fallopius. 

Chorda     Tympani     Nerve     (glosso- 

| 

palatine)  ,  to  the  tongue  and  palate. 

s  . 

"o 

Near      Stylo-  1 
mastoid          < 
Foramen. 

'/  Auricular. 
Post.  A  uncular  <  _     .   .    . 
\  Occipital. 

Br.  to  Digastric  muscle. 
Br.  to  Stylo-hyoid  muscle. 

C/3 

0) 

•S 

(  Temporal. 

d 

2 

f 

Temporo-facial  •<  Malar. 

pq 

1 

{  Infra-orbital. 

On  the  face.  *  \ 

(Buccal. 

I 

Mandibular. 

r 

Cervical. 

*  Forming  the  Pes  A  nserinus,  or  Goose's-foot,  as  these  branches  are  named. 


THE  CRANIAL  NERVES. 

71'1  Nerve -Facial,  or  Portia  Dura. 


PlateS 


References 

1  LargeSuperf.  Petrosal.toform  V«Jlan  wit 

2  Small  Supe^  PetrosaUo  Optic  Ganghor 

3  External  Superf.  Fetrosal,  to  Plaus  on  M 

4  Tympanic  Br  to  Stapedius.etc. 

3  Br  n-om  Carotid  Plexus.Making  Vidia^with  NOf 
).  7.  Eirs  to  Aur.culo  -Temporal  £  5 
V  Br  to  Auricular  of 


24Q 


250 


HUMAN   ANATOMY 


9th  NERVE, — Glossopharyngeal.         Functions, — Sensation,  Special  Sense. 
(See  page  221.) 


Communica-    j 

Large  Petrosal. 
Small  Petrosal. 

ting  Brs.  to   1 

Carotid  Plexus. 

Clrioiti                  ^ 

1  ympantc  or 

LJrigin. 
Tractus   soli- 
tarius  and  floor 

pth  Nerve 
Glosso- 

Jacobson's  N. 

Distributing    I 

Fenestra  vestibuli. 
Fenestra  cochlea?. 

of  4th  vent. 

pharyn- 

Brs.  to 

Eustachian  tube. 

and  the 

geal,  by 

Carotid  Branches,—  along  Int.  Carotid  artery. 

medulla  oblong. 

Jugular 

Pharyngeal  Br.  —  to  Pharyngeal  Plexus. 

behind  the 

Foramen. 

Muscular  Br.  —  to  Stylo-pharyngeus. 

olivary  body. 

Tonsillar  Brs.—  to  Tonsillar  Plexus. 

Lingual  Brs.  —  to  base  and  posterior  ^  of  tongue; 

nerve  of  taste. 

loth  NERVE,  —  Pneumogastric,  or  Vagus.         Function,  —  Motion,  Sensation. 

(See  page  221.) 

Meningeal,  to  dura  mater. 

Auricular  (Arnold's  Nerve),  to  external  ear. 

Pharyngeal,  to  that  plexus. 

Origin. 

Funic.    soli- 

Sup.  Laryngeal  <  T  Xt'T  aryng' 
(  Int.  Laryng. 

crico-thyroid). 
supplies     all     the 

tarius,  nucleus 

laryngeal 

ambiguus,  floor 

loth  Nerve 

Recurrent  Larynpf-f-l  • 

muscles  except 

of  4th  ventricle 

Vagus,  by 

Cervical  Car- 

crico-thyroid and 

and  the  medulla 

Jugular 

diac. 

to  cardiac 

arytenoideus. 

oblongata  be- 

Foramen. 

Thoracic  Car- 

plexus. 

tween  olivary 

diac. 

and  restiforn 
bodies. 

Ant.  Pulmonary.      \ 
-.         „   ,                    /-to  pulmonary  plexus. 
Post.  Pulmonary.    } 

(Esophageal,  to  that  plexus. 
Gastric  Brs.,  to  the  stomach. 
Hepatic,  to  the  hepatic  plexus. 


terminal  brs. 


Gives  sensation  to  external  ear  and  larynx,  motion  to  other  parts,  also  vaso- 
motor,  inhibitory,  trophic  and  secretory  influences.  A  nerve  of  deglutition,  phona- 
tion,  respiration,  circulation,  and  digestion.  The  Auriculo-Laryngo-Pharyngo- 
CEsophago-Tracheo-Pulmono-Cardio-Gastro-Hepatic  Nerve. 


nth  NERVE, — Spinal  Accessory  (N.  ACCESSORIUS). 
(See  page  222.) 


Function, — Motion. 


Origin. 

Floor  of  4th 

ventricle,  and 

gray  horn  of 

cord,  down  to 

6th  Cervical  N. 


nth  Nerve, 
by  Jugu- 
lar Fora- 
men. 


Branches,    to    Pharyngeal   and    Sup.    Laryngeal  of 
Vagus. 

Internal,    anastomosing    with  Vagus,    is    probably 
the  Recurrent  Laryngeal  Br.  of  the  latter  nerve. 

/  Sterno-mastoid. 
External,  or  Muscular,  tos  _ 

^  Trapezius. 


A  motor  nerve  to  the  muscles  named,  and  probably  to  the  larynx  also. 


Plate  9 
a,  THE  CRANIAL  NERVES. 

9'.*  or  Glosso-  pharyngeal, 
I0l.h  or  Pneumo gastric, 
II  fc.h  or  Spinal  Accessory. 


References. 

IJugular  Ganglion  of 3th Nerve 

Z.Petroui  Ganglion  of  9th  Nerve 

3.Ganglion  of  the  Vagu5  Rook. 

4. Ganglion  of  the  Vagus  Trunk. 

5. Medullary  part  OF  IP*  Nerve. 

6.Spinal  part  of  ||f."  Nerve. 

7  Sup  Cardiac  Br  JOINING  Cardiac  of  5ympafhetic 

8.5ubclavian  Artery  on  right  side,  Arch  of  the 

Aorla  on  left  side  of  the  body. 
9.Foramcn  Magnum,  receiving  5pinaf  part  of 

the  Spinal  Accessory. 

10.  Jugular  Foramen.transmitl'ng  all  three  Nerves 
II  Branches  to  the  Hypooloisal  Sympathetic 

cervical  fierves    ' 
12. Olivary  body,  (in  broken  line). 

Potter.del. 


251 


252 


HUMAN   ANATOMY 


6th  NERVE, — Abducens  (see  page  219). 

Origin. — A  nucleus 

in  floor  of  4th  ven- 
tricle, and  the       ^6th  Nerve,  Abducens. 
pyramid  of  the 
medulla  oblongata. 


Function, — Motion. 


Exit   by   sphenoidal    fissure   to   the 
Ext.  Rectus  muscle  of  the  eyeball. 
Branch,  to  the  sympathetic. 


8th  NERVE, — Auditory,  OR  ACUSTIC. 


Function, — Special    Sense. 


Origin. — Striae  in 

floor  of  the  4th 

ventricle,   and 

groove  between 

the  pons  and 

medulla. 


8th    Nerve, 
Auditory. 


f  2  Semi-circ.  canals. 
Vestibular,  toj  Utricle. 
[  Saccule. 

J  Post.  Semi-circ.  canal. 
Cochlear,  to      \  Saccule  and  Utricle. 

1  Cochlea,  and  Organ  of  Corti. 


A  nerve  of  special  sense  (hearing),  described  on  page  220,  ante.  It  goes  by  the 
Internal  Auditory  Meatus,  through  the  Internal  Auditory  Canal,  to  the  internal  ear. 
It  is  the  only  cranial  nerve  which  does  not  leave  the  cranial  wall. 


i2th  NERVE, — Hypoglossal  (NONUS  OR  QTH  OF  WILLIS). 

(See  page  222.)  Function, — Motor  of  tongue,  etc. 


Brs.  to 


Origin.  —  Floor  of 
4th  ventricle,  and 
groove  between 
the  pyramid  and 
olivary  body  of 
medulla.          J 

1  2th  Nerve, 
Hypoglossal. 

Descendens 
Hypoglossi. 

/  Lingual  of  5th. 
Communicating   I  Symphatic. 
I  i,  2  Cervical. 
(  Vagus. 

IBr.  to  Sterno-hyoid. 
Br.  to  Sterno-thyroid. 
Br.  to  Omo-hyoid. 
Joins    Communicans    Hypo- 
glossi. 

Thyro-hyoid,  to  that  muscle. 


Muscular,  to 


j  Stylo-glossus. 
I  Hyo-glossus. 
I  Genio-hyoid. 
[  Genio-hyo-glossus. 


Exit,  by  Ant.  Condylar  foramen  (Canalis  hypoglossi). 


THE  CRANIAL  NERVES. 

6th Nerve,-  Abducens. 


to  RectErter 


Plate  10 


riaal .Nerve^  of^ 

J&  ^ 


1 2**  Nerve, - 

Hypoglossal 
(Nonus  or  9^  of  Willis) 


.5**' 
Infra. 
. 3upnz-,  , 

4  Aunculo-temporal.SW 

5  Lachry 


7. 


., 
9.  Ibstertor  Auricular??* 


V 


Rjtter  del 


253 


and  0mo- 


254 


HUMAN   ANATOMY 


THE  SPINAL  NERVES 

8  CERVICAL,  12  THORACIC,  5  LUMBAR,  5  SACRAL,  i  COCCYGEAL 
N.  B. — Read  from  the  Black  Type  outwards  to  left  and  right 


Brs 

3,  to  Recticap.  Muscles. 

Post  Div.  of  2d  N. 

2  Cerv.  N. 

Post  M.  of  head,  etc.     POST.  ]  ist  Cerv 

cal    |  ANT.      Commun'g     Vagus  N. 

Complexus  Muscle.           Div.   \    Nerve. 

j    Div.        Brs.  to      |  Hypogl.  N. 

Skin  of  occiput. 

J  Sub-occij 

pital  ( 

Sup.   Cerv. 

Gang. 

Br. 

to  Occip-atloid  artic'n. 

Splenius 

Cerv.  ascendens 

Transv.-colli 

Ext.  Branch 

Br.  to  Spinal  accessory 

Trach-mastoid 

supplying 

Fil.to  Sterno-mastoidM. 

Complexus 

POST. 

.     ANT. 
Cervical 

Asc.  Br.  to  ist  Cerv.  N. 
Desc.  Br.  to  3d  Cerv.  N. 

to  ist  Cerv.  N. 

)lnt.  Br.  or 

Nerve. 

Fil.  to  Commun.  Hyp. 

Skin  of  occiput. 

Great  Occip. 

Occipitalis  Minor  N. 

Auricular. 

Auric.  Magnus  N. 

Splenius 

A  seen 

Superf.  Cervical  N. 

Cerv.  ascend. 

Ext.  Br. 

Br. 

Br.  to  2d  Cerv.  N. 

Trans,  colli 

supplies 

Br.  to  Spinal-ac. 

Trach-mast. 

POST.  1  .   3d 
n.,,      Cervic 

,    ANT.  • 
al  I  Div. 

Fil.  to  4th  Nerve. 

]  Int.   Br.        ""'  1     Nerv 
Integument       1 

of  occiput.       J 
J     supply 

e.  J                 Descen.     Fil.  to  Lev.  ang.  scap. 
Br.            Supra-clavicular. 
Fil.  to  Com.  Hypogl. 

Fil.  to  Phrenic  N. 

Fil.  to  3d  Cerv.  N. 

.    /  POST.  \   4th  Cervi 
Muscles  of  the  Back,  f     ^_    >         XT  

-al    f  ANT          FU"  tO  5th  CerV'  N> 
D.v      1  FiL  to  Phrenic  N" 

^      i-»iv.  j            nerve. 

Fil.  to  Scalenus  medius. 

I  Fil 

to  Supra-clavic.  N. 

A  nterior 
Divisions  of 
ist  Cerv.  N. 
2d  Cerv.  N. 
3d  Cerv.  N. 
4th  Cerv.  N. 


Cervical 
Plexus. 


Superficial 


Deep  Brs. 


(See  page  227.) 


Occipitalis  Minor,  to  head. 

I  Facial. 
Auricularis  Magnus  j  Auricular. 

(  Mastoid. 
Superficialis  Colli,  has  2  branches. 

I  Vagus. 
Communicating  to     j  Hypoglossus. 

|  Sympathetic. 

Muscular,  to  ant.  rectus  and  rect.  later. 
Communicans  Hypoglossi  N.  2. 
Phrenic  Nerve,  to  the  diaphragm. 
Muscular  4,  to  Sterno-mastoid,  etc. 
[  Communicating,  to  Spinal  accessory. 


THE  SPINAL  NERVES.        Hate  11 

Cervical  Plexus. 


Potter  .del 


/lCfo/r/fff{ 


The  Cervical  Plexus 


i...  iu     (      Scalenus  Medius  and      \  . 

lies  upon  the  Muscles 

ILevator  anguli  Scapulae  I 
is  covered   by  the  Sterno-Cleido-Mastoid  Muscle 

255 


256 


HUMAN    ANATOMY 


o 


THE  BRACHIAL  PLEXUS 
(See  page  228.)  Communicating  Br.  to  phrenic  nerve. 

Post,  or  Long  Thoracic,  I     to 
the  Ext.   Respiratory  I  Serrat. 
N.  of  Bell.  {     mag. 

,        f  Supra-spinatus. 
Supra-scapular,     T  ,          . 
^  <  Infra-spmatus. 

I  Shoulder-joint. 
Rhomboidei  (5,  6,  Cerv.) 
Subclavius   (5,  6.   Cerv.) 
Scaleni   (6,    7,    Cerv.) 
Long,  colli  (6,  7,  Cerv.) 
Lev.  ang.  scap.  (5,  Cerv.) 


Ant.    Div. 

5th 
Cervical 

Nerve. 

Ant.    Div. 

6th 

Cervical 
Nerve. 

Ant.    Div. 

7th 

Cervical 
Nerve. 

Ant.    Div. 

8th 

Cervical 
Nerve. 

Ant.    Div. 

ist 

Thoracic 
Nerve. 


UPPER 
PRI- 
MARY 
CORD. 


LOWER 

PRI- 

MARY 


Brach- 
ial 
Plexus,  i 


OUTER 
or  LAT- 
ERAL 
CORD. 


to 

Muscu- 
lar, to 


POSTERIOR 
CORD. 


INNER  or 
MEDIAL 
CORD. 


f  Br.  to  Post.  Cord  of  Brachial  Plexus. 
External  Ant.  Thoracic,  to  Pect. 
major. 

f  Muscular. 

Musculo-cutaneous.        I  Anterior. 
(No.  2.)  |  Posterior. 

[  Articular. 
Median  Nerve  (outer  head)  (No.  3). 

ist  Sub  scapular,  to  Subscap.  M. 
2d  Subscapular,  to  Lat.  dorsi. 
3d  Scapular,  to  Teres  major. 
Circumflex,    to    Deltoid    and    skin. 
(n.  Axillaris.) 

Musculo-spiral  f  Muscular< 
(No.  6). 
(n.  Radialis.) 


Cutaneous. 


Muscular, 
to 


Post.  Interosseous. 

[  Scaleni  (8,  Cerv.) 
|  Long,  colli  (8  Cerv.) 
I    Above  Clavicle. 
Br.  to  Post.  Cord  of  Brachial  Plexus. 
Int.     Ant.     Thoracic,     to     Pectoral 

muscles. 
Internal  Cutaneous  (No.  8)   (medial 

Anti-brachial  cutaneous). 
Lesser  Int.  Cutan.  (N.  of  Wrisberg) 

(medial  brachial  cutaneous). 
Median  Nerve  (inner  head)  (No.  3). 
Ulnar  Nerve  (No.  10). 


Note. — Nos.  i,  2,  3,  etc.,  refer  to  the  next  two  tables. 


THE  SPINAL  NERVES 

Brachial  Plexus 

Ulament  from 


Plate  12 


Cv 


/.  Three  <Sub- scapular  JVerm. 
2.  Internal  Ant.  Thoracic. 


Potter  del 


Jtfusculo-cutaneous 
'Median. 


Wnar 

Jnternal-culaneouj 


The  Brachial  Plexus  is 
in  the  Neck  and  the  Axilla, 
lym^  between  the  Anterior 
and  Middle  Scaleni  muscles 
at  first-  then  below  the  Sub- 
clavius  and  upon  the  1^ 
serration  of  theSerratus 
Magnus  and  Subscapulans. 
It  is  on  both  sides  of. and 
behind  the  Axillary  Artery 
in  its  2nd  Portion,  external 
.thereto  in  its  Ist  Portion. 


17 


257 


258 


HUMAN   ANATOMY 


NERVES  OF  THE     UPPER  EXTREMITY 

TERMINAL  BRANCHES  OF  THE  BRACHIAL  PLEXUS 


(i)  EXTERNAL  ANTERIOR  THORACIC,  to  Pectoralis  major  muscle. 

f  Coraco-brachialis. 

Muscular,  to..  •{  Biceps. 

[  Brachialis  anticus. 

i 

f  Skin  of  forearm  (front). 

8 

Anterior  Br.       -1  Skin  of  ball  of  thumb. 

1 

(2)  MUSCULO- 

{  Joins  Radial  Nerve. 

CUTANEOUS. 

a 

Skin  of  forearm  (back). 

1 

Posterior  Br. 

Joins  Radial  Nerve. 
Joins  Ext.  Cutan.  Br.  of  Musculo- 

3 

spiral  N. 

-8 

Articular  Br.,  to  Elbow-  joint. 

o 

f  Pronator  radii  teres. 

| 

Muscular,  to  .  . 

Flex,  carpi  radialis. 
Palm,  longus. 

'  6 

Flex.  subl.  digitorum. 

\ 

1 
c 

A  nterior 
Interosseous. 

to  Flex.  long,  pollicis. 
to  Flex.  prof,  digit.  (Ext.  H). 
to  Pronat.  quadratus. 

Palmar                 I  Skin  of  palm. 

Cutaneous.        \  Skin  of  ball  of  thumb. 

(3)  MEDIAN,  from 

both  outer  and 

to  Abduct,  pollicis. 

inner  cords. 

to  Opponens  pollicis. 

•A 

External   Br... 

to  Flex.  brev.  pollicis. 

§ 

Digital,  to  thumb. 

W 

Digital,  to  ist  finger. 

V 

a 

c 

Digital,  to  contiguous  sides  of  in- 

M 

Internal  Br.  .. 

dex,  middle  and  ring  fingers. 
Filaments,    to    two    outer    Lum- 

bricales. 

THE  SPINAL  NERVES.      Piste  13. 


250 


26o 


HUMAN   ANATOMY 
NERVES  OF  THE  UPPER  EXTREMITY.  — Continued. 

ist,  Upper,  to  Subscapular  muscle. 
U)SuBSCAPULAR3  {  2d,  Long,  to  Latiss.  dorsi. 
3d,  L'ower,  to  Teres  major. 


(5)  CIRCUMFLEX 
(n.  Axillaris). 


/  Deltoid. 

Superior    Br..to  <  „,  .      , 
\  Skin  of  i 


Skin  of  shoulder. 

Teres  minor. 

Inferior    Br..to    -j  Deltoid  (posteriorly). 
Skin  of  shoulder. 


(6)  MUSCULO- 
SPIRAL   (n. 
Radialis). 


Muscular ...  to 


f  Triceps.  Anconeus. 
I  Brach.  anticus. 
I  Supin.  longus. 
[  Extensor  carpi  long. 


Cutaneous,  to  skin  of  arm. 


f  External  Br.  to  skin  of  thumb. 


Radial, 


]  Internal  Br. 


I  to  ulnar  side  of  thumb  and  ad- 
\    jacent  sides  of  2^  fingers. 


ito  all  muscles  on  back  of  forearm, 
except   Anconeus,    Sup.    long,    and 
Extensor  carpi  longior. 
Filaments  to  wrist-joints. 

(7)  INTERNAL  ANTERIOR  THORACIC,  to  both  Pectoral  muscles. 

(8)  INTERNAL  CUTANEOUS  (  Anterior  Br.  to  skin  of  forearm,  inner  side, 
(med.  Ant.  Brach.  Cuta.)  \  Posterior  Br.  to  skin  of  forearm,  inner  side. 

(9)  LESSER  INTERNAL  CUTANEOUS,  f  Is    often     wanting,     Intercosto-humeral 

(N.  of  Wrisberg.)  -j     taking    its    place,    to    post,    surface    of 

(medial  Brach.  Cutan.)  1     lower  H  of  skin  of  arm. 


Articular,  .  . 

.  .  to  Elbow-joint. 

i 

Muscular,  .  . 

f  Flex.  carp,  ulnaris. 
'    °  \  Flex.  prof.  dig.  (inner  }£) 

8 

£  ' 

c 

Cutaneous,  to  skin  of  front  wrist,  and  palm  of  hand. 
Dorsal  Cutaneous,  to  skin  of  back  wrist,  and  iji  fingers. 

(10)  ULNAR 

Articular,  .  .  . 

.  to  Wrist-joint. 

i 

rt 

a 
i—  i 

Superficial 
Palmar,  ,  .  . 

(  Palmaris  brevis. 
to\  Skin  of  iH  fingers. 

(Muscles  of  little  finger. 
2  inner  Lumbricales. 

InterosseL 

Dt.r.t  "Pn.lm.nv 

Adduc.  pollicis. 

Flex.  brev.  poll,  (inner  headV 


THE   THORACIC    NERVES 


26l 


THE  THORACIC  NERVES 

N.  B.—Read  from  the  Black  Types  outwards  to  left  and  right 


Transv.  colli. 

Muscu-     {  Intercos. 

Longis.  dorsi. 

lar.          \  Tri.  Ster. 

Trachelo-mast. 

Ext.  Brs. 

Levat.  costar. 

<—  to 

Skin  of 

Sacro-lumbal. 

{   Each  of    1 

ANT. 

Lateral 

Chest, 

Aocessorius. 

POST.)    Upper  6    1 

Div. 

Cutane- 

Breast. 

Div.  |    Thoracic   | 

Thoracic 

ous. 

Side, 

I  Nerves.   J 

Inlercostals. 

Back. 

Semi-sp.  dorsi. 

r  Int.    Brs. 

A  nterior 

f  Skin  of 

Multif.     Spinae.  • 

«—    tO 

Cutane-  < 

Chest, 

Skin  of  back. 

ous. 

,    Breast. 

Muscu-     (  Intercos. 

Same  as  above. 

.    Z7..J        D—  - 

ANT. 

lar.          \  Abdom.  M. 

Skin  of  back. 

*  iLxt.  &rs. 

Div.  or 

(Each  of  1 

Thorac- 

Lateral       (  Skin  of 

Lower  6    1 

ico-ab- 

Cutane-  j 

Abdomen, 

Thoracic  J 

dominal 

ous.         {    etc. 

Same  as  above. 

\, 

Nerves.  J 

Inter- 

No. br.  of  skin.  > 

>  Int.   Brs. 

costal*. 

Anterior    (  Recti  M. 

Cutane-  j     Skin  of 

ous. 

Abdomen. 

1 2th 
Thoracic 


•ANT.  Div. 


/Also  sends  a  branch  to 
1  the  Lumbo-sacral  Cord. 


262 


HUMAN    ANATOMY 
THE  LUMBAR  AND  SACRAL  NERVES 

(See  page  232) 
(DISTRIBUTION  SHOWN  ON  THE  NEXT  TWO  TABLES) 


An                 |     1 

[         Nos. 

^^    Branch,     g        Ist  Lumbar  /  Ant.            i,  2,  3, 
sending  filaments     >                                [     Div.  |    Comm.  Br. 

to  the  Erector        g     J 

(  to  2d  Lum. 

spinae  and          o 

Intertransversales    JB     1 

Nos. 

muscles,  and  the     ^ 
skin  of  the  gluteal    °       ^  Lumba, 

.     f  Ant.            3,  4,  7, 
\     Div.      Comm.  Br. 

region,  posteriorly.    ^     J 

to  3d  Lum. 

Lumbar    Plexus. 

3 

Branches: 

1  1 

{Part  of 

(i)  Ilio-hypogastric. 

5,  6.  7, 

(2)  Ilio-inguinal. 

Internal  Branch,     -J3     |  3 

Comm.  Br. 

(3)  Genito-  crural. 

sending  filaments     Q    J 

to  4th  Lum. 

(4)  Ext.   Cutaneous. 

to  the  Multifid.       ^ 

(5)  Obturator. 

spinae,  and  Inter-    -g 

f       Part  of 

(6)  Accessory 

spinales,  and  the    -g 
skin  over  spinal      £     j-  4th  Lumba 

/Ant.             r5'V 
r.  <     ^.            Lumbo- 

Obturator. 
(7)  Anterior  Crural. 

vertebras.             <u 

*        1V'           5acra/ 

e  J 

Cord 

\ 

r  A.,      f    Joins  the    ' 

g     [  5th  Lumbar.  <  ""T    {      Lumfeo- 

4«                -     J 

[  Sacra/  Cora1 

External  Branch, 

forming  loop  on       £ 

f    Joins  the 

sacrum  and  great    c 

/  Ant            Lumbo- 

Sac-Sciat.   lig.   to     g        ist  Sacral. 

1     nj^      Sacra/  Cord 

supply   skin   over    £ 

I     •L'lv.                   j 
and 

glutei.               "3 

2d  Sacral. 

*     [ad  Sacral. 
"8 

/  Ant.    /  Joins  with 
\     Div.  \   ist  Sacral. 

Sacral   Plexus. 

Branches: 

a 

(i)  Sup.  Gluteal. 

An               1 

f  Joins  with 

(2)  Inf.  Gluteal. 

Internal  Branch,      >      I 
to  Multifidus  Spinae  S      |3d 

2d  Sacral 
and  part 

(3)  Muscular. 
(4)  Articular. 

and  skin  of  the       £     J 

[   of  the  4th. 

(5)  Small  Sciatic. 

gluteal  region;  the    % 

(6)  Pudic. 

lower  nerve  to        g 

Br.  to 

(7)  Great  Sciatic. 

Extensor  Coccygis   & 

f  Ant             PleXUS> 

and  skin  over  the  jg       4th  Sacral. 

i     Div        Visc'Brs- 

coccyx. 

Mus.  Brs. 

J 

Fil.  to  5th.   . 

Join  together  in 

loops  over  back     Post.   \ 
of  sacrum,             Div./5*  SaCraL 

/  Ant.     (  Br.  to  skin  of  coccyx. 
\     Div.  j  Br.  to  Coccygeus  M. 

sending  fila- 

[ Br.  to  Cocc.  Nerve. 

ments  to  skin 

over  coccyx         Post.   \  _ 

f  Ant.    /  A  delicate  filament,  going  to  skin 

and  Extensor          Div.  / 

\  Div.    \    over  coccyx. 

Coccygis. 

Plate  14 

THE  SPINAL  NERVES. 

lumbar  &  Sacral  Plexuses. 


The  lumbar  Plexus  lies  in  the  Substance  of  the  Psoas  Muscle 
( Lies  upon  the  Pyr  iformis  Muscle  in  the  Pelvis 

The  Sacral  Plexus  {and  is  covered  by  the  Pelvic  Fascia, and  the 
V  Sciatic  and  Pudic  Arteries. 
Potter,  del 


264 


HUMAN   ANATOMY 


ILIO-HYPOGASTRIC, 
from  ist  Lumbar. 


DISTRIBUTION   OF  THE  BRANCHES 
FROM  THE  7  GREAT  TRUNKS  OF  THE  LUMBAR  PLEXUS 
(A  CONTINUATION  OF  THE  TABLE  ON  PAGE  261) 

f  Iliac,  to  skin  of  gluteal  region. 

j  Hypogastric,  to  skin  of  that  region. 

(  Communicating  Br.,  with  I2th  thoracic  nerve. 


ILIO-INGUINAL, 

from  ist  Lumbar. 


Branch,  to  ilio-hypogastric  nerve. 

to  Internal  Oblique  muscle. 

to  skin  of  upper  and  inner  thigh,  scrotum. 


GENITO-CRURAL,  \  Genital,  to  Cremaster,  scrotum,  round  ligament, 

or  GENITO-FEMORAL      <j  Crural,  to  skin  of  upper  and  front  thigh, 
from  ist,  2nd  Lumbar.  [  Branch,  to  femoral  artery. 

EXTERNAL  CUTANEOUS,  (  Ant.  Br.  to  skin  of  ant.  and  outer  thigh, 
from  2nd,  3d  Lumbar.  \  Post.  Br.  to  skin  of  post,  and  outer  thigh. 


OBTURATOR, 
from    2d,    sd 
4th  Lumbar. 


Ant.     I"  Articular  Brs.  to  hip-joint. 
Br.    j  Muscular  Brs.  to  Adductors,  Gracilis  and  Pectineus. 

[  Anastotnotic  Brs.  with  Int.  Cutan.  and  Int.  Saphenous. 

Post.    \  Articular  Brs.  to  knee-joint. 
Br.    \  Muscular  Brs.  to  Adduc.  mag.  and  Obturator  externus. 


ACCESSORY  OBTURATOR, 


from  3d,  4th  Lumbar. 


Muscular  Br.  to  Pectineus. 
Articular  Br.  to  hip- joint. 


f  often  absent. 


Cutaneous  Br.  to  skin  of  thigh  and  leg.  J 
Muscular  Brs.  to  Iliacus  muscle. 


Arterial,  to  the  femoral  artery. 


>  within  abdomen. 


ANTERIOR 

Mid.  Cutaneous. 

to  Sartorius,  and  skin  of  ant.  thigh 
as  low  as  the  knee. 

FEMORAL  or 

Ant. 

Ext.  Br.  to  skin,  lateral  of  knee. 

CRURAL, 

Div. 

Int.  Cutaneous. 

Post.  Br.  to  skin  of  inner  thigh  and 

from    2d,    3d, 

leg. 

4th  Lumbar. 

Long  Saphenous. 

to    skin    of   knee   and    of    front    and 
inner  leg  and  foot. 

p          |  Muscular  Brs.  to  the  4  parts  of  the  Quadriceps  Extensor 

*£T  j     muscle. 

V'  [  Articular  Brs.  2,  to  capsules  of  knee-  and  hip-joints. 

The  Lumbar  Plexus  lies  in  the  substance  of  the  Psoas  muscle,  in  front  of  the  trans- 
verse processes  of  the  lumbar  vertebrae. 


THE  SPINAL  NERVES. 


Plate  15 


Potter,  del 


266 


HUMAN   ANATOMY 


DISTRIBUTION  OF  THE  BRANCHES  OP  THE  SACRAL  PLEXUS 
[CONTINUATION  OF  TABLE  ON  PAGE  261] 


SUPERIOR  GLUTEAL, 
from  Lumbo-sacral  cord.  I  Inf.  Br. 


Sup.  Br.  to  the  Gluteus  medius  muscle. 

to  the  Gluteus  medius  and  minimus, 
to  the  Tensor  vaginae  femoris. 


INFERIOR  GLUTEAL,.  .to  the  Gluteus  maximus  muscle. 


MUSCULAR  BRANCHES,  to 


Pyriformis,  Obturator  internus,  the  two  Gemelli,  and 


the  Quadratus  femoris  muscles. 
ARTICULAR  BRANCHES,  to  the  hip- joint. 


SMALL  SCIATIC, 
or  POSTERIOR 
FEMORAL 
CUTANEOUS, 
from  2d,  3d  Sac- 
ral. 


Gluteal  Cutaneous,  to  skin  over  Gluteus  maximus. 


Perineal  Cutaneous,     *°  ^  *  "Pf  ^  and  finner  thigh' 
[  Inf.  Pudendal,  skin  of  scrotum. 


Femoral  Cutaneous 


0   back   °f   thigh,   popliteal   space,    and 
upper  part  of  the  leg. 


PERFORATING          f 

CUTANEOUS,  1  to  skin  covering  lower  part  of  Gluteus  maximus  muscle:  passes 

from  2d,  3d  Sac-  ]     through  the  sacro-sciatic  ligament. 
ral. 


PUDIC  or 
PUDENDAL, 
from      3d,      4th 
Sacral. 


GREAT  SCIATIC 
(n.  ischiadicus), 
from    lumbo-sac- 
ral  cord,  4  upper 
sacral. 


Inferior  Hemorrhoidal, 


to  Sphincter  ani  muscle, 
to  skin  of  anal  region. 


(to    Skin    of    anus,    scrotum, 
Superficial  Perineal,   -j     penis    and    labia,    and    the 
(    Sphincter  ani  muscle. 
Muscular,  to  perineal  muscles,  and  corpus  spongio- 
sum  of  penis. 


Dorsal  of  Penis, 


Skin  of  dorsum  of  penis. 
Br.  to  Corpora  cavernosa. 


Articular,,  .to  the  hip-joint. 

Adductus  magnus,  Biceps. 


Muscular,  to 


Semi-mem branosus,  Semi-tendinosus. 


External  Popliteal  or  Peroneal.  \  terminal  branches. 

Internal  Popliteal  or  Tibial  Nerve.   }     (See  next  page.) 


The  Sacral  Plexus  lies  in  the  pelvis  upon  the  Pyriformis  muscle,  and  is  covered 
by  the  Pelvic  fascia,  and  the  Sciatic  and  Pudic  arteries. 


NERVES  OF  THE  LEG  AND  FOOT 


267 


INTERNAL 

POPLITEAL 

or  TIBIAL 

NERVE. 


NERVES  OF  THE  LEG  AND  FOOT 

TERMINAL  BRANCHES  OF  THE  GREAT  SCIATIC  NERVE] 
Articular  3,  to  knee-joint. 

Muscular,  to  Gastrocnemius,  Plantaris,  Soleus,  and  Popliteus. 
Communicans  Tibialis,  to  form  the  Ext.  Saphenous  nerve. 

I  formed  by  a  filament  from  each  of  the 

External  or  Short  Saphenous,  j     Popliteal    nerves,    to    skin    of   outer 
1     side  of  the  foot  and  little  toe. 


Continues 
as  the— 

POSTERIOR 
TIBIAL. 


Muscular,  to 


Flexor    longus     pollicis.     Flexor    longus    digitorum. 


Tibialis  posticus.     Soleus. 
Calcaneo-Plantar,  to  skin  of  heel  and  sole  of  the  foot. 
Articular,  to  the  ankle-joint. 

I  Digital,  to  skin,  3^  inner  toes. 
Internal  I  Muscular,  to  flexors,  etc. 

Plantar.         J  Articular,  to  tarsal  joints. 
I  Cutaneous,  to  sole  of  foot. 


External 
Plantar. 


Muscular,  to  Flexor  accessorius. 

f  to  I  ^j  outer  toes. 
Superficial,         <  Flexor  brevis  min.  digiti. 

[  4th  Interosseous. 


Deep  Br.  to  the 


3d  and  4th  Lumbricales. 
rest  of  Interossei. 


EXTERNAL 
POPLITEAL 
or  COMMON 
PERONEAL 
NERVE. 


Articular  3,  distributed  to  the  knee-joint. 
Cutaneous  2,  to  skin  of  leg,  exteriorly  and  posteriorly. 
Communicans  Peronei,  to  form  the  Ext.  Saphenous  nerve. 
/  front  muscles  of  leg. 


Anterior 
Tibial cr 
Deep  Pero- 
neal 


Musculo- 
cutaneous  or 
Superficial 
Peroneal. 


Muscular,  to 


External  Br. 


\  Peroneus  tertius. 

/  Extensor  brevis  digitorum. 


\  Tarsal  articulations. 
Internal  Br.  to  skin  of  sides  of  great  and  2nd  toes. 


External  Br. 


Peroneus  longus  and  brevis  muscles. 
Skin,  outer  side  of  foot  and  ankle. 
Skin,  contig.  sides,  3d,  4th,  5th  toes. 


[  Skin,  inner  side  of  foot  and  ankle. 
Internal  Br.       -j  Skin,  contig.  sides,  ad  and  3d  toes 
[    and  inner  side  of  great  toe. 


268 


HUMAN   ANATOMY 


Begins  in 
the— 


1  Ganglio 
/    of  Ribes 


External 

Sup. 

Branches 

Brs. 

to  join  the 

ist,  2d, 

Superior 

3d,  4th 

Cervical  • 

Anter 

Cervical 

Ganglion. 

Nerves. 

THE  SYMPATHETIC  SYSTEM 

n    f  on  the  Anterior  Communicating  artery,  at  the  base  of 
es.  \    the  brain. 

[  Some  to  Pneumogastric,   Glossopharyngeal,  and 
Hypoglossal  Nerves. 

(Ext.  Br.  forms  Carotid  Plexus. 
Int.  Br.  forms  Cavernous  Plex. 
along  Int.  Carotid  Artery. 
Anterior  Branches,  to  Plexus  on  Ext.  Carotid  Artery. 

f  Pharyngeal,  to  Pharyngeal  Plexus. 

Int.      I  Superior  Cardiac  Nerve,  to  Cardiac  Plexus;  goes 
Brs.  I     to   Deep   PI.   on   right  side,   to   Superficial   PI. 
[    left  side  of  body. 


Ext.  Brs.  to  f  Middle 

5th  and  6th  j  Cervical 

Cerv.  N.    [  Ganglion. 

Ext.  Brs.  to  f  Inferior 

7th  and  8th  X  Cervical 

Cerv.  N.    [  Ganglion. 


Int. 
Brs. 


(Filaments  along   Inf.    Thyroid   Art.   to   Thyroid 

•j     body  and  Larynx. 

[  M id.  Cardiac  Nerve,  to  Deep  Cardiac  Plexus. 


Int.      (  Filaments  along  Vertebral  Art.  to  cranium. 
Brs.  \  Inf.  Cardiac  Nerve,  to  Deep  Cardiac  Plexus. 


Ext.  Brs.  to 
Thoracic 

N. 


f        "        1 
•j    Thoracic    j- 

[    Ganglia.   J 


Int. 
Brs. 


Upper  5  or  6  to  Aorta  and  Vertebral  column. 

3d  and  4th  to  Post.  Pulmonary  Plexus. 

Lower  6  form  the  3  Splanchnic  Nerves,  thus — 

6-10,  Great  Splanchnic,  to  Semi-lunar  Gang. 
10,    ii.    Lesser    Splanchnic,    to    Cceliac    Plexus. 

12,    Smaller   Splanchnic,    to    Renal    and    Solar 

Plexuses. 


Ext.  Brs.  to 
Lumbar  N. 


4 

Lumbar 
Ganglia. 


lnt.      1  Some  to  Aortic  Plexus. 
Brs.  \  Some  to  Hypogastric  Plexus. 


Ext.  Brs.  to 
Sacral  N. 


4  or  5 

Sacral 

Ganglia. 


Int 
Brs 


'.      f  to  Pelvic  Plexus. 

rs.  \  to  Plexus  on  Middle  Sacral  Artery. 


{Coccygeal  ) 
G.,  or       I  In    which   ends   the   double   chain   of   gangliated   cords 
Ganglion    j    enumerated  above,  and  called  THE  SYMPATHETIC  NERVE. 
Impar.     . 


[FOR  THE  VARIOUS  CONNECTED  GANGLIA,  ETC.,  SEE  PAGES  223  TO  22?.] 


THE  SYMPATHETIC 
SYSTEM  OF  NERVES 


Plate  16 


tcG.ofRootofPncu 
toftlrvas  G. 
Glasso-pha 

from  &Cervica 

•2 


G^GANGLIOTJ 


umogastric 
toflypoylos&al  N. 

br.  cf£xt.  Carotid  A . 


toPharyntjeal  P. 
to  Inf. 'Thyroid  4* 


Cardiac  bT.Jr.PneumogastTic  f?=  PLEXUS  . 
and  Rec.  Larynyeal  "Nerves    AJ=ARTERY. 


"Cardiac  Fiexns 

Mexua 


duodenal 


/.  Sup.  HemorrhoidaL  P. 
2.Spcrmatic  Plexus 


rpoaa&tric  Plexus 

Pelvic  or  Inf. '  ffypcyra&tnc  Plexn* 


Oarujlumlmpar.    ^        Twt«r  del. 
26<) 


2  7o 


HUMAN   ANATOMY 


FIG.  81. 


ORGANS  OF  SPECIAL  SENSE 

The  Special  Senses  are  those  of  touch,  taste,  smell,  sight  and  hearing. 
The  Skin  is  the  principal  seat  of  the  sense  of  touch,  the  Tongue  is  the  organ 
of  taste,  the  Nose  is  the  peripheral  organ  of  smell,  the  Eye  of  sight  and  the 
Ear  of  hearing. 

THE  SKIN  AND  ITS  APPENDAGES 

The  Skin  consists  of — the  Epidermis  or  Cuticle,  the  scarf-skin,  com- 
posed of  3  superficial  and  2  deep  layers;  and  the  Derma,  Corium,  or  Cutis 
Vera,  the  true  skin,  composed  of  a 
papillary  layer  above  and  a  reticular 
layer  below. 

The  Epidermis,  Cuticle  or  Scarf- 
skin,  is  an  unorganized  epithelial 
structure,  having  neither  vessels  nor 
nerves.  Its  constituent  epithelial 
cells  are  agglutinated  together  in  a 
laminated  arrangement,  are  flat  and 
dry  on  the  surface,  round  and  softer 
in  the  central  portion,  columnar  and 
softest  in  the  deepest  layers.  They 
are  arranged  in  the  following  layers, 
from  above  downward,  viz. — 

Stratum  Corneum  (i), — horny  epi- 
thelial cells,  without  nuclei. 
Stratum  Lucidum, — closely  packed, 

scaly  cells. 

Stratum  Granulosum, — flat,  spin- 
dle-shaped cells,  containing 
granules  of  eleidin,  an  interme- 
diate substance  in  the  forma- 
tion of  horn. 

Rete  Mucosum  or  Stratum  Mal- 
pighii  (2), — contains  pigment 
cells. 

Basilar    Layer    or    Stratum    Germinativum, — composed    of    columnar 

epithelial  cells  placed  perpendicularly  on  the  surface  of  the  derma,  and 

separated  from  the  papillae  by  a  homogeneous  basement  membrane. 

The  Derma,  Corium  or  Cutis  Vera  (4),  the  true  skin,  is  a  highly  organized, 

tough  yet  elastic  tissue,  and  serves  to  protect  the  parts  beneath,  to  perform 


APPENDAGES    OF    THE    SKIN  271 

the  functions  of  excretion  and  absorption,  and  as  the  chief  seat  of  the  sense 
of  touch.     It  consists  of  felted  connective  tissue,  elastic  fibres,  blood- 
vessels, lymphatics,  and  nerves;  also  unstriped  muscular  fibres  in  various 
situations.     It  is  formed  in  two  layers,  as  follows: — 
Papillary  Layer  (3), — situated  next  to  the  epidermis,  is  covered  with 
minute  conical  elevations  (papillae),  H^oo  inch  high,   ^50  inch  in 
diameter  at  their  base,   very  numerous  and  arranged  in  parallel 
curved  lines  wherever  sensibility  is  greatest.     Each  papilla  contains 
a  capillary  loop  or  plexus,  the  termination  of  one  or  more  sensory 
nerves, — and  in  highly  sensitive  parts,  an  oval-shaped  body,  the 
Tactile  Corpuscle,  a  special  sensory  nerve  ending. 

Reticular  Layer, — the  deep  layer,  is  composed  chiefly  of  interlacing  bun- 
dles of  white  fibrous  tissue,  in  which  are  mingled  some  yellow  elastic 
fibres;  also  plain  muscular  fibres  wherever  hairs  are  found,  and  lym- 
phatic vessels,  blood-vessels,  and  nerves  in  plexiform  arrangement. 
Below  this  the  elements  of  the  skin  become  blended  with  the  sub- 
cutaneous tela  or  areolar  tissue  (5),  which  contains  fat,  except  in  a  few 
situations. 

Mucous  Membrane  is  a  soft,  velvety  structure,  analogous  to  the  skin, 
and  found  as  the  lining  of  the  gastro-intestinal,  pulmonary  and  genito- 
urinary tracts.  It  is  composed  of — Epithelium  of  various  forms,  in- 
cluding the  squamous,  columnar,  and  ciliated,  often  arranged  in  several 
layers;  and  Corium,  analogous  to  the  derma  of  the  skin,  consists  of  con- 
nective tissue,  blood-vessels,  lymphatics,  nerves,  and  unstriped  muscle 
cells;  and  is  separated  from  the  epithelium  by  a  transparent  basement 
membrane.  The  mucous  membrane  has  numerous  glands  embedded  in 
it,  which  secrete  mucus  to  cover  the  surface  for  its  protection  from  foreign 
substances.  Projecting  from  it  in  certain  parts  are  villi  and  papilla. 
processes  which  are  analogous  to  the  papillae  of  the  skin. 

Structures  lying  in  the  Skin,  and  directly  beneath  it,  include  the  follow- 
ing, viz. — 

Sensitive  Papilla,  containing  Tactile  Corpuscles  in  very  sensitive  parts, — 

in  the  papillary  layer  of  the  derma. 
Hair  Follicles, — in  the  reticular  layer  of  the  derma,  perforating  the 

derma  and  the  epidermis:  sometimes  extending  into  the  subcutaneous 

tissue. 
Sebaceous  Glands  (6), — in  the  reticular  layer  of  the  derma;  their  ducts 

(8,  9)  opening  usually  into  the  hair-follicles,  but  occasionally  on  the 

surface  of  the  epidermis. 
Sudoriferous  or  Sweat  Glands, — usually  in   the  subcutaneous  areolar 


272 


HUMAN   ANATOMY 


FIG.  82. 


tissue;  their  ducts  perforating  the  derma  and  epidermis,  to  open  on 
the  surface  of  the  latter. 

Fat  Cells, — in  the  subcutaneous  areolar  tissue. 
Organs  of  Touch  are  the  various  sensory  nerve- 
endings  in  the  skin  or  its  vicinity  and  in  mucous 
membranes.  They  include  minute,  primitive 
fibrilla  or  networks  thereof,  and  certain  special 
terminal  organs,  as  follows: — 

End-bulbs  of  Krause, — minute  bodies,  Moo 
inch  in  diameter,  consisting  of  a  capsule 
surrounding  a  soft  core,  in  which  the  axis- 
cylinder  of  the  nerve  terminates,  in  a  bulbous 
expansion  or  in  a  coiled  plexiform  mass. 
They  are  found  chiefly  in  mucous  mem- 
branes, the  genital  organs,  and  the  synovia] 
membranes  of  the  finger-joints. 
Tactile  Corpuscles, — are  oval  bodies,  ^oo  inch 
long,  formed  of  connective  tissue,  and  con- 
sisting of  a  capsule  and  imperfect  septa,  which  penetrate  the  interior. 
The  axis-cylinders  of  the  nerve  fibres  (N)  terminate  within  the 
corpuscle  in  a  globular  enlargement.  They  are  found  in  papillae  of 
the  derma  of  the  hand,  foot,  forearm,  lips, 
nipple,  etc.  Other  tactile  corpuscles,  in 
the  papillae  of  parts  devoid  of  hair,  consist 
of  a  capsule,  containing  two  or  more 
granular  cells,  between  which  the  nerve- 
fibre  is  supposed  to  terminate. 
Pacinian  Corpuscles, — are  composed  of 
lamellae  (d),  consisting  of  connective 
tissue  fibres,  arranged  concentrically 
around  a  central  clear  space  (ni),  in  which 
the  nerve-fibre  (n)  terminates  at  the  distal 
extremity  in  a  rounded  end  (a),  which  is 
often  bifid  or  even  trifid.  They  are  found 
chiefly  on  the  nerves  of  the  palm  of  the 
hand  and  the  sole  of  the  foot,  the  ends  of 
the  fingers,  and  the  genital  organs,  lying 
in  the  subcutaneous  tissue. 

APPENDAGES  or  THE  SKIN 

The  Nails  (Ungues)  are  curved,  horny  structures,  a  modification  of  the 
epidermis,  molded  upon  the  derma  at  the  dorsal  surface  of  the  terminal 


FIG.  83. 


THE    TONGUE  273 

phalanges  of  the  fingers  and  toes.  Each  nail  is  convex  on  its  outward 
surface,  and  is  embedded  by  its  Root  (radix  unguis)  into  a  fold  of  the  skin. 
Its— 

Matrix, — is  that  portion  of  the  derma  directly  beneath  the  nail.     It  is 

covered  with  highly  vascular  papillae.     The — 

Lunula, — is  a  white  crescentic  portion  of  the  nail  nearest  to  its  root, 

produced  by  the  diminution  in  number  and  size  of  the  papillae  beneath. 

The  Hairs  (Pili)  are  also  a  modified  form  of  the  epidermis,  found  over 

nearly  the  whole  surface  of  the  body,  much  varied  in  size  and  color.     Each 

hair  consists  of  a  Root  and  a  Shaft.     The — 

Root  (radix  pili), — is  lodged  in  an  involution  of  the  epidermis  called  the 
Hair-follicle,  which  sometimes  extends  into  the  subcutaneous  cellular 
tissue.     The  root  rests  on  a  vascular  papilla,  at  the  bottom  or  Bulb 
of  the  follicle,  which  supplies  it  with  material  for  its  growth. 
Shaft  (scapus  pili), — is  the  projecting  portion  of  the  hair.     It  consists 
of  a  medulla  in  the  centre,  next  a  fibrous  portion,  externally  a  cortex 
of  thin,  flat  scales.     The  finest  hairs  have  no  medulla. 
Point  (apex  pili), — consists  of  the  fibrous  portion  and  the  cortex,  the 

medulla  being  wanting. 

Sebaceous  Glands  (Glandulae  Sebaceae)  are  small,  glandular  bodies 
situated  in  the  corium  over  most  of  the  body,  but  not  in  that  of  the  palmar 
surface  of  the  hands  nor  on  the  plantar  surface  of  the  feet.  Each  gland 
consists  of  a  single  sacculated  duct,  usually  opening  into  a  hair-follicle, 
but  sometimes  ending  on  the  surface  of  the  epidermis.  They  are  most 
abundant  in  the  scalp,  the  face,  around  the  anus,  and  the  apertures  of  the 
nose,  mouth  and  external  ear.  The  largest  are  the — 
Meibomian  Glands, — situated  in  the  eyelids. 

Sudoriferous  or  Sweat  Glands  (Glandulae  Sudoriferae)  consist  each  of  a 
single  convoluted  tube,  situated  usually  in  the  subcutaneous  cellular 
tissue,  and  opening  on  the  surface  of  the  integument  by  a  spiral  duct 
which  pierces  the  derma  and  the  epidermis.  The  duct  has  two  coats,  an 
external  fibro-cellular,  which  is  continuous  with  the  corium,  and  an 
epithelial  lining,  continuous  with  the  epidermis.  These  glands  are 
estimated  as  varying,  in  different  parts  of  the  integument,  from  417  to 
2800  to  the  square  inch,  giving  for  the  whole  body  a  total  number  of  nearly 
two  millions  and  a  half,  representing  an  evaporating  surface  of  about  8 
square  inches.  They  are  most  numerous  on  the  palm  of  the  hand. 

THE  TONGUE  (LINGUA) 

The  Tongue  is  the  organ  of  taste.     It  is  composed  of  siriated  muscle, 
is  covered  with  mucous  membrane,  and  is  supplied  with  blood-vessels, 
18 


274 


HUMAN    ANATOMY 


lymphatics  and  nerves.  Its  base  (radix  linguae)  is  connected  with  the 
hyoid  bone  by  the  hyo-glossi  and  genio-hyo-glossi  (mm.  genioglossi) 
muscles  and  the  hyo-glossal  membrane;  with  the  epiglottis,  by  the  3 
gJosso-epiglottic  folds  of  mucous  membrane;  with  the  soft  palate,  by  the 
anterior  pillars  (arci  glosso-palatini)  of  the  fauces;  and  with  the  pharynx, 
by  the  superior  constrictor  muscles  and  the  mucous  membrane.  Its  tip 
(apex  linguae),  thin  and  narrow,  is  free  in  the  mouth,  and  rests  when 
quiet  against  the  lower  incisor  teeth.  Its  wider  surface  (facies  inferior 
linguae)  is  connected  with  the  lower  jaw  by  PIG 

the  genio-hyo-glossi  (mm.  genioglossi)  mus- 
cles. Its  mucous  covering  is  reflected  later- 
ally on  the  inner  surface  of  the  gums,  form- 
ing in  front  the  frjEnum  lingua  (frenulum  lin- 
guae), a  vertical  fold  below  the  tip.  The 
tongue  presents  the — 

Raphe  (sulcus  medianus  linguae), — a  ver- 
tical, fibrous  septum,  in  the  median  line, 
dividing  the  tongue  into  two  symmet- 
rical halves,  and  terminating  behind  in  a 
depression,  the  foramen  ctzcum,  about  an 
inch  from  the  base  of  the  organ. 
Papillcs  V dilates  (i)  (circumvallate), — 8  to  12 
in  number,  in  two  rows  on  the  dorsum  of 
the  tongue,  the  rows  forming  a  V  and 
meeting  in  front  of  the  foramen  cacum. 
Papilla  Fungiformes  (2)  (lenticular), — 
scattered  irregularly  over  the  dorsum, 
chiefly  at  its  sides  and  apex. 
Papilla  Filiformes  (conical), — cover  the  anterior  two- thirds  of  the 
dorsum  and'  have  numerous  filiform  processes  or  secondary  papillae 
projecting  from  their  apices. 

Taste-buds, — flask-shaped  bodies,  found  in  the  epidermis  of  the  circum- 
vallate papillae,  and  in  some  of  the  fungifqrm  (described  below). 
Glands  of  Blandin  or  Nuhn, — mucous  glands,  one  on  either  side  of  the 
fraenum,  having  4  to  6  ducts  which  open  on  the  under  surface  of  the 
apex. 
Racemose  Serous  Glands  of  Ebner, — at  the  back  of  the  tongue,  their  ducts 

opening  into  the  fossae  of  the  vallate  papillae. 
Hyo-glossal  Membrane, — a  strong,  fibrous  lamina,  connecting  the  under 

surface  of  the  base  of  the  tongue  to  the  bod>  of  the  hyoid  bone. 
Extrinsic  Muscles  of  the  Tongue, — are  the  stylo-,  hyo-,  chondro-,  genio- 


THE    TONGUE  275 

hyo-,  palato-glossi  muscles,  and  part  of  the  superior  constrictors  of 
the  pharynx  (pharyngeo-glossi).  These  have  been  described  on 
page  82. 

Intrinsic  Muscles  of  the  Tongue, — are  the  various  fibres  of  the  lingualis 
muscle, — superior,  inferior,  transverse  and  vertical.     (See  page  83.) 
Taste-buds  are  flask-shaped  bodies,  situated  in  the  epidermis  (e)  of  the 
vallate  and  some  of  the  fungiform  papillae;  also  found  at  the  sides  of  the 
base  of  the  tongue,  on  the  epiglottis  and  the  soft  palate.     Each  bud  has  a 
broad  base,  which  rests  on  the  corium,  and  a  neck  opening  on  the  mucous 
surface  by  an  orifice,  the  gustatory  pore  (0).     The  buds  are  formed  by  sup- 
porting  cells,  mostly  arranged  like  the  staves  of  a 
cask;  and  spindle-shaped,  nucleated  gustatory  cells 
in  the   central  portion,  each   terminating  at  the 
gustatory  pore   in   a  fine  filament,  the  gustatory 
hair.     Terminal  nerve-fibrils  ramify  between  the 
gustatory  cells,  and  others  are  found  between  the 
cortical  cells. 

Vessels  of  the  Tongue.  The  Arteries  are  de- 
rived from  the  lingual,  facial,  and  ascending 
pharyngeal,  branches  of  the  external  carotid. 
The^  Veins  open  into  the  internal  jugular.  The 
Lymphatics  of  the  posterior  half  of  the  tongue 
pass  to  one  or  two  small  glands  on  the  hyo-glossus 
muscle,  and  thence  to  the  deep  glands  of  the  neck; 

those   of   the   anterior   half    are   connected    with    the    sub-mandibular 
lymphatics. 

Nerves  of  the  Tongue  are  as  follows:  the — 

Lingual  Branch  of  the  Mandibular  Division  of  the  $th, — to  the  papillae  of  the 
fore  part  and  sides  of  the  tongue,  endowing  the  anterior  two-thirds  of  the 
organ  with  ordinary  sensibility. 

Chorda  Tympani  is  the  continuation  of  the  glosso-palatine  nerve  (n.  inter- 
medius)  or  "pars  intermedia, "  the  sensory  root  of  the  facial, — it  runs  in 
the  sheath  of  the  lingual  nerve  and  is  distributed  to  the  same  region, 
being  the  nerve  of  taste  for  the  anterior  two-thirds  of  the  tongue. 

Lingual  Branches  of  the  gth  or  Glosso- pharyngeal, — to  the  mucous  membrane 
of  the  base  and  sides  and  the  circumvallate  papillae,  being  the  nerves  of 
taste  and  ordinary  sensation  for  the  posterior  third  of  the  tongue. 

Hypo-glossal  or  j  2th  Nerve, — the  motor  nerve  of  the  tongue,  distributed  to 
the  intrinsic  and  extrinsic  muscles, 


276  HUMAN   ANATOMY 

Superior  Laryngeal  Branch  of  the  loth  or  Vagus, — sends  a  few  filaments,  by 
way  of  its  internal  laryngeal  branch,  to  the  root  of  the  tongue. 

Sympathetic  Filaments, — from  the  nervi  molles  on  the  lingual  and  other 
arteries  supplying  the  organ  (Spitzka). 

Special  Nerves  of  Taste  in  the  Tongue,  are  the- 
Chorda  Tympani,  the  continuation  of  the  sensory  root  (glosso-palatine 

nerve  or  n.  inter medius)  of  the  Facial, — for  its  anterior  two- thirds; 

perceiving  saline,  acid  and  styptic  qualities  (Flint). 
Lingual  Branches  of  the  Glosso-pharyngeal, — for  its  posterior  third;  appre- 
ciating alkaline,  metallic,  sweet  and  bitter  tastes  (Flint). 

Sapolini's  view  of  the  Chorda  Tympani  Nerve.  From  repeated  dis- 
sections, Dr.  Sapolini,  of  Milan,  believes  the  chorda  tympani  to  be  a 
separate  cranial  nerve,  a  continuation  of  the  pars  intermedia  of  Wrisberg 
(glosso-palatine  nerve  or  n.  intermedius)  which  has  its  deep  origin  in  the 
upper  end  of  the  nucleus  of  the  glosso-pharyngeal  nerve  in  the  floor  of 
the  4th  ventricle  and  the  solitary  or  "trineural"  tract  in  the  medulla, 
joins  the  facial  in  the  internal  auditory  meatus,  and  terminates  in  a  dense 
plexus  with  the  lingual  branch  of  the  £th  in  the  muscular  substance  of  the 
tongue.  He  further  concludes  that  the  chorda  tympani  is  the  nerve 
governing  the  movements  of  the  tongue  in  speech,  and  that  the  nerves  of 
taste  are  the  Lingual  Branches  of  the  5th  and  gth  nerves. 

THE  NOSE  (NASUS) 

The  Nose  is  the  peripheral  organ  of  smell,  and  consists  of  the  outer  nose 
(nasus  externus)  and  the  nasal  fossae  (cavum  nasi).  The  Outer  Nose 
projects  from  the  centre  of  the  face,  and  is  composed  of  a  framework 
of  bones  and  cartilages,  covered  by  skin,  lined  by  mucous  membrane,  and 
supplied  with  vessels  and  nerves.  At  its  base  it  presents  two  elliptical 
orifices,  the  nostrils  or  anterior  nares,  separated  by  a  septum,  the  columna 
(septum  mobile  nasi),  and  guarded  at  their  margins  by  numerous  stiff 
hairs,  the  mbrissoe.  The — 

Bony  Framework, — is  formed  by  the  nasal  bones  and  the  nasal  processes 
of  the  maxillae  (see  page  27). 

Cartilages  (cartilagines  nasi)  are  5, — two  upper  lateral  (cartilago  nasi 
latralis),  two  lower  lateral  (cartilago  alaris  nasi  major),  and  the 
cartilage  of  the  septum  (cartilago  septi  nasi),  connected  together  and 
to  the  bones  by  a  tough,  fibrous  membrane,  which  permits  of  free 
movement  between  them. 
Septum  Nasi,  the  nasal  septum, — is  formed  anteriorly  by  the  cartilage 


THE    NOSE 


277 


of  the  septum,  posteriorly  by  the  perpendicular  plate  of  the  ethmoid 
bone  above  and  the  vomer  below. 

The  Nasal  Fossae  (cavum  nasi)  are  two  irregular  cavities  in  the  middle 
of  the  face,  separated  by  the  septum  nasi,  opening  in  front  by  the  anterior 
nares,  behind  by  the  posterior  nares  (choanae)  into  the  naso-pharynx. 
Their  osteological  description  has  been  given  on  page  37.  Each  fossa  is 
divided  into  an  olfactory  portion  (regio  olfactoria),  containing  the  upper 
part  of  the  septum  and  the  superior  turbinal  process  and  a  respiratory 
portion  (regio  respiratoria),  comprising  the  rest  of  the  fossa.  It  is 
further  divided,  from  above  downward,  into  the  superior,  middle  and 


16     H  12 

inferior  meatuses  of  the  nose,  which  are  separated  from  each  other  by  the 
middle  (concha  nasalis  media)  (2)  and  inferior  turbinal  (concha  nasalis 
inferior)  bones.  Each  fossa  presents  the — 

Vestibule  (9), — a  slight  dilatation  inside  the  aperture  of  the  nostril, 
extending  as  a  small  pouch,  the  ventricle,  toward  the  point  of  the  nose. 
Spheno-ethmoidal  Recess, — on  the  outer  wall,  above  the  superior  tur- 
binal process  into  which  the  sphenoidal  sinus  (4)  opens. 
Bulla  Ethmoidalis, — an  elevation  on  the  outer  wall  of  the  middle  meatus, 

on  or  above  which  are  the  orifices  of  the  middle  ethmoidal  cells. 
Hiatus  Semilunaris, — a  narrow  groove  in  the  outer  wall,  in  front  of 
the  bulla  ethmoidalis,  into  which  open  the  anterior  ethmoidal  cells 
and  the  antrum  (sinus  maxillaris)  of  Highmore  (i) . 
Infundibulum  (3), — the  superior  prolongation  of  the  middle  meatus, 


278  HUMAN   ANATOMY 

leading   into   anterior  ethmoidal   cells   and   the  frontal   sinus    (see 
page  38). 
Atrium  (atrium  meatus  medii  nasi)  (5), — a  depressed  area  above  the 

vestibule,  forming  the  anterior  extremity  of  the  middle  meatus. 
Orifice  of  the  Nasal  Duct  (ductus  naso-lacrimalis)  (7), — on  the  outer  wall, 

in  the  anterior  part  of  the  inferior  meatus. 

Naso-palatine  Recess, — a  depression  at  the  lower  edge  of  the  cartilage  of 

the  septum;  near  it  a  minute  orifice  leads  into  a  blind  pouch,  the 

rudimentary  organ  of  Jacobson  (organon  vomero-nasale). 

The  Schneiderian  or  Pituitary  Membrane  is  the  mucous  membrane 

lining   the  nasal  fossae,   thick   and   vascular   over  the  septum  and  the 

turbinal  processes,  but  very  thin  elsewhere.     On  it,  in  the  upper  portion  of 

the  fossae,  are  distributed  the  terminal  filaments  of  the  olfactory  nerve,  the 

FIG.  87. 


special  nerve  of  the  sense  of  smell.  It  is  continuous  with  the  mucous  lin- 
ing of  the  pharynx,  Eustachian  tube  (tuba  auditiva),  tympanum  and 
mastoid  cells;  also  with  that  of  the  frontal,  ethmoidal  and  sphenoidal 
sinuses,  the  maxillary  antrum,  nasal  duct,  and  the  conjunctiva.  It  is 
covered  with  columnar  epithelium,  which  is  ciliated  throughout  most  of 
its  extent,  contains  much  adenoid  tissue,  is  provided  with  mucous  and 
serous  glands,  and  in  the  olfactory  region  it  contains  the — 

Olfactory  Cells  of  Schultze, — spindle-shaped,   epithelial  cells,  grouped 
around  and  between  the  columnar  cells  of  the  epithelium,  having  at 


THE    NOSE  279 

one  end  hair-like  processes,  the  olfactory  hairs,  and  joined  together  by 

other  processes,  forming  an  intricate  plexus  on  which  the  terminal 

fibres  of  the  olfactory  nerves  are  supposed  to  end. 
Glands  of  Bowman, — are  tubular,  often  branched,  serous  glands,  in  a 

layer  beneath  the  epithelium,  extending  through  the  thickness  of  the 

mucous  membrane,  in  the  olfactory  region. 

Nerves  supplying  the  Outer  Nose  are  branches  from  the  facial  nerve 
to  the  muscles;  branches  from  the  infraorbital  and  infratrochlear,  and  the 
nasal  branch  of  the  ophthalmic,  supplying  the  integument.  Those 
supplying  the  Nasal  Fossa  are  the — 

Olfactory  or  ist  Nerve  (a), — over  the  upper  third  of  the  septum  (i),  the 

superior  turbinal  process  and  the  surface  of  the  ethmoid  in  front  of  it. 
Nasal  Branch  of  the  Ophthalmic  (d}, — to  the  septum  and  outer  walls. 
Anterior  Dental  or  Alveolar  Branch  of  the  Maxillary, — to  the  inferior 

meatus  of  the  nose  and  the  inferior  turbinal  bone. 
Vidian  Nerve  (n.  canalis  pterygoidei), — to  the  septum  and  the  inferior 

turbinal  bone. 
Naso-palatine  (e), — from  the  spheno-palatine  ganglion,  to  the  middle  of 

the  septum;  thence  through  the  anterior  palatine  foramen  (/). 
Anterior  Palatine  (h), — from  the  spheno-palatine  ganglion,  to  the  middle 

and  lower  turbinal  bones,  by  its  inferior  nasal  branches. 
Superior  Nasal  Branches, — from  the  spheno-palatine  ganglion,  to  the 

septum  and  the  superior  and  middle  turbinal  bones. 

Arteries  of  the  Nose.  The  arteries  supplying  the  Outer  Nose  are — 
the  lateralis  nasi  branch  of  the  facial  (a.  maxillaris  externa);  the  inferior 
artery  of  the  septum,  from  the  superior  coronary  branch  of  the  facial 
(a.  maxillaris  externa);  and  the  nasal  branch  of  the  ophthalmic  and  the 
infraorbital,  which  go  to  the  dorsum  and  sides  of  the  nose.  The  Arteries 
of  the  Nasal  Fosses  form  a  close,  plexiform  network  beneath  and  in  the 
mucous  membrane,  and  are  the — • 

Ant.  and  Post.  Ethmoidal,  from  the  ophthalmic, — to  the  roof. 
Spheno-palatine,  branch  of  the  internal  maxillary, — to  the  mucous  mem- 
brane over  the  turbinal  bones,  the  meatuses,  and  the  septum. 
Infraorbital  and  Alveolar,  branches  of  the  internal  maxillary, — to  the 

mucous  lining  of  the  antrum. 

Inferior  Artery  of  the  Septum,  from  the  superior  coronary  branch  of  the 
facial    (a.    maxillaris   externa), — to   the   mucous   membrane   of   the 

septum. 

. 
Veins  of  the  Nose.     Those  of  the  outer  nose  terminate  in  the  facial  and 

ophthalmic  veins.     Those  of  the  nasal  fossa  form  a  close,  cavernous-like 


280 


HUMAN   ANATOMY 


network  beneath  the  mucous  membrane,  and  terminate  in  the  facial  and 
ophthalmic  veins,  a  few  going  to  the  veins  in  the  interior  of  the  skull. 


THE  EYE 

[For  an  osteological  description  of  the  Orbit,  see  page  35.] 

The  Eyeball  (bulbus  oculi)  is  situated  in  the  anterior  part  of  the  orbital 

cavity,  on  a  cushion  of  connective  tissue  and  fat,  where  it  is  retained  by 

its  muscles,  the  optic  nerve,  the  conjunctiva,  etc.,  and  protected  in  front 

by  the  eyelids  and  eyebrows.     It  is  composed  of  segments  of  two  spheres 

of  different  sizes;  the  anterior  segment  being  the  smaller,  forming  about 

Y§    of    the    eyeball,  and  named  the  cornea;  the  posterior  and  larger 

segment,  is  formed  by  the  sclerotic  coat 

(tunica  fibrosa  oculi),  and  constitutes 

the  remaining  %   of  the  globe.     It  is 

surrounded  by  a  thin,  membranous  sac, 

the  capsule  (fascia  bulbi  oculi)  of  Tenon, 

and  has  the  following —  '< 

Diameters, — in  the  adult,  antero-pos- 

terior    and    transverse,    nearly    an 

inch,  vertical  about  %o  of  an  inch. 

Anterior  Pole, — the  central  point  of 

the  anterior  curvature. 
Posterior  Pole, — the  central  point  of 

the  posterior  curvature. 
Sagittal  Axis    (axis  optica), — a  line 

joining  the  two  poles. 
The  Capsule  of  Tenon  (fascia  bulbi 
oculi)  (3)  is  a  thin  membrane  which  en- 
velops the  eyeball  from  the  optic  nerve 
to  the  ciliary  region,  where  it  blends  with  the  ocular  conjunctiva.  Its 
smooth,  inner  surface  is  in  contact  with  the  outer  surface  of  the  scler- 
otic coat  (tunica  fibrosa  oculi),  with  which  it  is  connected  by  delicate 
bands  of  connective  tissue.  Posteriorly  it  is  continuous  with  the  sheath 
(17)  of  the  optic  nerve,  and  from  it  tubular  sheaths  are  prolonged  over 
the  muscles  which  move  the  eyeball,  giving  off  slips  to  the  bones  of  the 
orbit.  The — 

Check  Ligaments, — internal  and  external,  are  expansions  from  the 
sheaths  of  the  internal  and  external  recti  muscles,  and  are  attached 
to  the  lacrimal  and  malar  bones  respectively. 


THE    EYE  28l 

Suspensory  Ligament  of  the  Eye  (Lock wood's), — is  a  thickening  of  the 

lower  part  of  the  capsule,  slung  like  a  hammock  below  the  eyeball, 

and  attached  to  the  lacrimal  and  malar  bones. 
Peri-sclerotic  Lymph-space, — intervenes  between  the  capsule  and  the 

sclerotic,  and  is  continuous  with  the  subdural  and  subarachnoid 

spaces. 

Tunics  of  the  Eyeball  are  3  in  number,  named  from  without  inward  as 
follows:  the — 
;     Sclerotic    (fibrosa)    (3)   and  Coronea   (i), — the  external,   fibrous,  and 

protective  tunic. 
Choroid  (choroidea)  (4),  Ciliary  Body  (corpus  ciliare)   (5),  and  Iris  (8), 

— the  vascular  tunic,  sometimes  called  the  Uveal  Tract. 
Retina  (tunica  interna)    (13), — the  innermost,  nervous  tunic. 

Refracting  Media  are  3  in  number,  and  are  named  as  follows:  the — 
Aqueous  Humor  (humor  aqueus)  (2),  ^fills  the  anterior  (2)  and  posterior 

(9)  chambers  (camerae). 

Vitreous  Body  (corpus  vitreum)  (18), — fills  the  concavity  of  the  retina. 
Crystalline  Lens  (lens  crystallina)  (15), — in  front  of  the  vitreous  body. 

THE  SCLEROTIC  AND  CORNEA 

The  Sclerotic,  or  hard  coat  (tunica  fibrosa  oculi),  is  the  posterior  five- 
sixths  of  the  jjx.t£rnal  iunic  of  the  eyeball,  the  anterior  one-sixth  being  the 
Cornea.  Externally  it  is  of  a  whita-color,  covered  anteriorly  by  the 
conjunctival  mucous  membrane,  posteriorly  being  continuous  with  the 
fibrous  sheath  of  the  optic  nerve.  Internally  its  color  is  brown,  and  its 
surface  marked  by  grooves  for  the  ciliary  nerves.  The  optic  nerve  pierces 
it  posteriorly,  also  the  long  and  short  ciliary  arteries,  posterior  ciliary 
veins  and  short  ciliary  nerves.  In  the  equatorial  region  it  is  pierced 
obliquely  by  the  venae  vorticosae,  and  around  the  corneal  border  by  the 
anterior  ciliary  arteries  and  veins.  It  is  composed  of  white  fibrous  tissue, 
intermixed  with  elastic  fibres,  and  of  flattened  connective-tissue  corpuscles, 
some  of  which  are  pigmented.  The  Sclerotic  presents  for  consideration 
the  following  points: — 

Thickness, — ^5  inch  posteriorly,  %o  inch  anteriorly. 

Lamina  Fusca, — a  layer  of  very  fine  pigmented  connective  tissue,  con- 
necting the  sclerotic  with  the  outer  surface  of  the  choroid. 

Lamina  Cribrosa  (lamina  cribrosa  sclerae), — the  posterior  perforated 
portion  of  the  sclerotic,  which  at  this  point  is  a  thin,  cribriform 
lamina.  Its  largest  opening  transmits  the  arteria  centralis  retinae. 


282  HUMAN    ANATOMY 

Arteries, — from    the    ciliary,   are  few  and  in  a  coarse  network,   the 

capillaries  uniting  at  long  and  wide  intervals. 
Nerves, — from  the  ciliary,  their  mode  of  ending  unknown. 

The  Cornea,  or  horny  body,  is  the  anterior  transparent  projecting 
portion  of  the  external  tunic  of  the  eyeball,  forming  about  one-sixth 
thereof.     It  is  set  into  the  sclerotic  as  a  watch-crystal  into  its  case,  is  of 
nearly  circular  base,  and  its  curvature  varies  in  degree  in  different  persons, 
and  in  the  same  person  at  different  ages,  becoming  flattened  in  advanced 
life.     It  consists  of  4  layers, — centrally  the  true  fibrous  corneal  tissue, 
having  in  ^ront   the  conjunctival  epithelium;   behind,   a   homogeneous 
elastic  lamina  and  thyepithelial  lining  of  the  anterior  chamber.     The — 
Conjunctival  Epithelium, — consists  of  several  layers  of  epithelial  cells, 
the  deepest  being  columnar,  the  central  polyhedral   with   processes 
and  the  superficial  scaly  with  flattened  nuclei. 

Jj  Proper  Corneal  Substance, — a  transparent,  firm,  fibrous  structure,  con- 
tinuous with  the  sclerotic,  and  composed  of  about  60  lamella  of 
modified  connective  tissue,  superimposed  one  on  the  other,  and 
connected  by  a  cement,  in  which  are  spaces  of  stellate  shape,  each 
containing  a  cell,  the  corneal  corpuscle.  The  anterior  layer  of  the 
corneal  substance  was  called  by  Bowman  the  anterior  elastic  lamina. 
Posterior  Elastic  Lamina,  Membrane  of  Descemet,  or  Demours, — is  a 
structureless  basement  membrane,  of  extreme  thinness  and  trans- 
parency, the  latter  being  unaffected  by  water,  alcohol  or  acids;  very 
brittle,  exceedingly  elastic,  and  curls  up  inwardly  upon  itself,  when 
detached  from  the  true  cornea.  At  the  corneal  margin  it  breaks  up 
into  fibres,  some  of  which  are  continuous  with  the  ligamentum 
pectinatum  of  the  iris. 

Fontana' s  Spaces  (spatia  anguli  iridis), — are  small,  cavernous  spaces 
between  the  fibres  which  go  to  form  the  ligamentum  pectinatum. 
In  some  animals,  as  the  ox,  they  form  regular  canals.  They  com- 
municate with  the  anterior  chamber  and  with  the — 

X  j    Canal  of  Schlemm,  or  Sinus  Venosus  Sclerce, — a  minute  canal  at  the 
internal  corneo-sclerotic  junction,  extending  around  the  circumfer- 
ence of  the  attached  border  of  the  iris.     It. communicates  with  the 
anterior  chamber  through  the  spaces  of  Fontana,  also  with  the  scleral 
v       veins. 

Posterior  Endothelial  Layer  (endothelium  cameras  anterioris), — a  single 
layer  of  flattened,  polygonal,  transparent,  nucleated  cells,  covers 
the  posterior  surface  of  the  elastic  lamina,  lines  the  anterior  chamber 
and  the  spaces  of  Fontana,  and  is  reflected  on  to  the  front  of  the  iris. 


THE    EYE  283 

Vessels, — none,  the  capillary  vessels  terminating  in  loops  at  its  circum- 
ference, so  that  it  is  practically  a  non-vascular  structure. 
^  j Nerves,— are  numerous;  24  to  36  twigs  from  the  Ciliary  nerves  form  an 
intricate  plexus  throughout  its  laminated  substance. 

THE  CHOROID,  CILIARY  BODY  AND  IRIS 

The  Middle  Tunic  (Tunica  Vasculosa  Oculi)  of  the  Eye  is  formed  from 
behind  forward  by  the  Choroid,  the  Ciliary  Body  and  the  Iris;  the  former 
being  the  vascular  ami  pigmented  tunic;  the  latter  a  circular,  muscular 
curtain  or  septum,  with  the  pupil,  an  opening  in  its  centre;  while  the  ciliary 
body  connects  the  choroid  with  the  iris. 

The  Choroid  is  a  thin,  vascular  membrane,  of  dark-brown  or  chocolate 
color,  which  invests  the  posterior  ^  of  the  globe,  extending  from  the 
optic  nerve  entrance  behind  to  the  ora  serrata  of  the  retina.     It  is  loosely 
connected  externally  by  the  lamina  fusca  to  the  sclerotic,  the  space  be- 
tween being  the  peri-choroidallymph-space,  and  is  covered  by  a  thin  mem- 
brane, the  lamina  superchoroidea,  containing  spaces  between  its  constituent 
lamellae.     Internally  it  is  connected  with  the  pigmentary  layer  of  the  retina 
by  the  lamina  basalis  or  membrane  of  Bruch,  a  very  thin,  structureless 
membrane.     The  Choroid  terminates  anteriorly  in  the  ciliary  processes 
(see  below),  and  is  composed  of  2  layers,  as  follows: — 
Lamina  Vasculosa,  the  external  layer, — consists  chiefly  of  the  venae 
vorticosae,  the  larger  branches  of  the  short  ciliary  arteries,  and  dark 
pigment  cells. 

Lamina  Chorio-capillaris  or  Tunica  Ruyschiana,  the  internal  layer, — 
consists  of  a  very  fine  capillary  plexus,  formed  by  the  short  ciliary 
vessels. 
Tapelum, — is  the  name  applied  to  the  iridescent  appearance  seen  in  the 

outer  and  posterior  part  of  the  choroid  of  many  animals. 
Arteries, — are  the  short  ciliary  and  recurrent  branches  from  the  long 

and  anterior  ciliary  arteries. 
Veins  (2), — unite  into  4  or  5  trunks  (4),  which  pass  out  through  the 

sclerotic  near  its  equator. 
Nerves  (3), — are  derived  from  thej^d,  $th  and  sympathetic,  through  the 

long  ciliary  and  the  ciliary  branches  of  the  ophthalmic  ganglion. 
The  Ciliary  Body  (corpus  ciliare)  (5),  comprises  the  orbiculus  ciliaris, 
(annulus  ciliaris),  the  ciliary  processes,  and  the  ciliary  muscle.     It  con- 
nects the  choroid  with  the  circumference  of  the  iris.     The — 

Orbiculus  Ciliaris  (annulus  ciliaris), — is  a  zone  about  ^  inch  wide, 
directly  continuous  with  the  anterior  part  of  the  choroid. 


284  HUMAN   ANATOMY 

Ciliary  Processes, — are  60  to  80  folds,  formed  by  the  plaiting  of  the 
choroid  and  its  lamina  basalis  at  their  anterior  margin,  and  are 
received  into  corresponding  folds  of  the  suspensory  ligament  of  the 
lens.  They  form  a  sort  of  plaited  frill  behind  the  iris,  around  the 
margin  of  the  lens,  and  are  similar  in  structure  to  the  choroid. 

Ciliary  Muscle  or  Muscle  of  Bowman  (m.  ciliaris) , — is  a  ring  of  un- 
striped  muscular  fibres  on  the  outer  surface  of  the  anterior  part  of 
the  choroid,  and  consists  of  radiating  (fibrae  meridianales)  and  cir- 
cular fibres  (fibrae  circulares).  The  former  arise  from  the  corneo- 
sclerotic  junction  and  pass  backward  to  the  choroid  in  front  of  the 

PIG.  89. 


Nerves 


Sclera 


retina.  The  circular  fibres  are  internal  to  the  radiating  ones,  have  a 
circular  course  around  the  attachment  of  the  iris,  and  by  drawing 
on  the  ciliary  processes  they  relax  the  suspensory  ligament  of  the 
lens,  permitting  the  lens  to  become  more  convex  by  its  own  elasticity. 
It  is  supplied  by  the  3d  nerve. 

The  Iris  (6)  is  a  perforated  contractile  curtain,  suspended  in  the  aqueous 
humor  behind  the  cornea  and  in  front  of  the  lens,  and  is  the  anterior 
portion  of  the  middle  tunic  of  the  eyeball,  being  continuous  with  the 
ciliary  body  and  the  choroid.  It  is  about  %  inch  wide,  K  o  o  inch  thick,  and 
is  composed  of  radiating  and  circular  muscular  fibres,  a  fibrous  stroma  and 
pigment  cells,  covered  by  a  layer  of  endothelial  cells  continuous  with  those 
of  the  posterior  elastic  lamina  of  the  cornea.  The — 


THE    EYE  285 

Pupil  (pupilla), — is  the  central  opening  in  the  iris,  situated  a  little  to 
the  nasal  side  of  the  centre,  diameter  >^2  to  Y±  inch. 

Ligamentum  Pectinatum  Iridis,  or  Dollinger's  band, — is  the  suspensory 
ligament  of  the  iris,  connecting  its  ciliary  margin  with  the  posterior 
elastic  lamina  of  the  cornea. 

Pars  Iridica  Retina  or  Uvea, — pigmented  epithelium  of  deep  purple 
color,  on  the  posterior  surface  of  the  iris. 

Sphincter  Pupillce, — a  layer  of  circular  muscular  fibres  around  the  pupil- 
lary margin,  supplied  by  the  3d  nerve. 

Dilator  Pupilla, — radiating  muscular  fibres  from  the  pupillary  margin 
toward  the  ciliary  border,  supplied  by  fibres  of  the  sympathetic  from 
the  ciliary  ganglion. 

Membrana  Pupillaris, — a  vascular  membrane  which  covers  the  pupil  in 
the  foetus,  disappearing  about  the  eighth  month,  occasionally  perma- 
nent. 

Arteries, — are  derived  from  the  long  and  anterior  ciliary,  forming  the 
circulus  major  at  the  ciliary  border,  and  the  circulus  minor  near  the 
pupillary  margin. 

Veins, — empty  into  those  of  the  ciliary  processes  and  the  anterior 
ciliary  veins. 

Nerves  of  the  Iris, — are  derived  from  the  3d,  5th  and  the  sympathetic, 
through  the  long  and  short  ciliary  nerves.  The  3d  supplies  the 
circular  fibres,  the  sympathetic  the  radiating  ones,  the  5th  being 
nerves  of  common  sensation. 

THE  RETINA  (TUNICA  INTERNA) 

The  Retina,  the  innermost  or  nervous  tunic  of  the  eye,  is  a  delicate, 
grayish,  transparent  membrane,  about  ^75  of  an  inch  thick  at  the  fundus, 
3^oo  inch  at  the  anterior  margin.  It  is  formed  by  a  membranous  ex- 
pansion of  the  optic  nerve  elements,  and  extends  from  the  termination  of 
that  nerve  nearly  as  far  forward  as  the  ciliary  processes,  terminating  in  a 
jagged  margin,  the  or  a  serrata,  though  its  fibrous  stroma  is  continued  as 
the  pars  ciliaris  retina  over  the  ciliary  body.  The  Retina  presents  for 
examination  the  following  points: — 

Macula  LiUea,  or  Yellow  Spot, — situated  on  the  retina,  exactly  in  the 
visual  axis;  in  an  elevated  oval  spot  where  vision  is  very  acute,  the 
retina  being  very  thin  and  full  of  nerve  elements  closely  packed 
together  at  the  expense  of  its  connective  tissue.  No  rods,  no  nerve- 
fibre  layer  here,  but  the  cones  and  ganglion-cells  are  very  numerous. 
Fovea  Centralis, — a  depression  at  the  centre  of  the  macula  lutea,  M  25 
to  Ko  inch  in  diameter,  in  which  the  sense  of  vision  is  most  acute. 


286  HUMAN   ANATOMY 

Porus  Opticus  or  Optic  Disk, — the  point  where  the  optic  nerve  enters, 
lies  about  %  inch  internal  to  the  yellow  spot.  It  is  often  called  the 
blind  spot,  being  the  only  part  of  the  fundus  from  which  the  power  of 
vision  is  absent. 

Cotticulus  Nervi  Optici  or  Optic  Papilla, — is  a  slight  eminence  of  the 
nervous  substance  at  the  porus  opticus;  the  central  artery  of  the 
retina  pierces  its  centre  which  is  depressed  slightly,  forming  the 
Optic  Cup  (excavatio  papillae  nervi  optici). 

Pars  Ciliaris  Retina, — is  that  portion  of  the  retinal  stroma  which  is 
prolonged  over  the  ciliary  body,  and  continued  over  the  back  of  the 
iris  as  the  pars  iridica  retina.  It  is  destitute  of  nerve-elements. 

Arteries  of  the  Retina, — arise  from  the  arteria  centralis  retinas  (branch 
of  the  ophthalmic  artery),  just  behind  the  porus  opticus;  run  chiefly 
upward  and  downward,  accompanied  by  veins,  to  terminate  in  a 
minute  capillary  plexus.  They  do  not  anastomose  with  each  other, 
being  terminal  arteries.  No  vessels  exist  in  the  fovea  centralis,  and 
only  the  finest  capillaries  in  the  macula  lutea. 

Structure  of  the  Retina.  The  retina  is  composed  of  nervous  elements, 
blood-vessels,  pigmented  epithelium,  and  modified  connective  tissue  re- 
sembling the  neuroglia  of  the  brain;  the  latter  being  called  the  radiating 
fibres  or  fibres  of  Mutter,  which  form  the  two  limiting  membranes  and 
stretch  between  them,  passing  through  all  the  nervous  layers  except 
Jacob's  membrane.  The  structures  are  arranged  in  10  layers,  as  follows: — 

Membrana  Limitans  Interna, — derived  from  the  supporting  frame-work 
and  shown  in  the  cut  by  the  lowest  line. 

Layer  of  Nerve-fibres  (stratum  opticum)  (i), — formed  by  the  expansion 
of  the  optic  nerve,  the  fibres  of  which,  as  simple  axis-cylinders,  pass 
through  all  the  succeeding  layers  of  the  retina. 

Ganglionic  Layer  (2), — a  single  layer  of  large  ganglion-cells,  which  give 
off  their  axons  into  the  preceding  layer  and  their  dendrites  into  the 
inner  molecular  layer. 

Inner  Plexiform  Layer  (3), — is  made  up  of  a  dense  reticulum  of  minute 
fibrils,  formed  by  the  interlacement  of  the  dendrites  of  the  ganglion- 
cells  with  those  of  the  cells  of  the  next  layer. 

Inner  Nuclear  or  Granular  Layer  (4), — consists  of  closely  packed  cells  of 
3  kinds,  bipolar,  amacrine,  and  cells  connected  with  the  fibres  of 
Miiller. 

Outer  Plexiform  Layer  (5), — a  dense  network  of  minute  fibrils  derived 
from  the  processes  of  the  cells  in  the  adjoining  layers. 

Outer  Nuclear  or  Granular  Layer  (6), — contains  several  strata  of  oval 
nuclear  bodies,  named  rod-granules  and  cone  granules,  which  are 


THE   EYE 


287 


FIG.  90. 


respectively  continuous  with  the  rods  and  cones  of  Jacob's  membrane. 
Membrana  Limitans   Externa, — derived   from   the   supporting   frame- 
work of  the  retina,  is  shown  in  the  cut  by  a  horizontal  line  between 
layers  6  and  7. 

Jacob's  Membrane,  or  Layer  of  Rods  and  Cones  (7), — the  perceptive 

portion  of  the  retina,  is  composed  of  a 
palisade-like  arrangement  of  rods  and 
cones,  the  terminal  organs  probably 
of  the  optic  nerve  fibres. 
Pigmentary  Layer,  or  Tapetum  Nigrum 
(8), — formerly  described  as  a  part  of 
the  choroid,  consists  of  a  single  layer 
of  hexagonal  epithelial  cells,  loaded 
with  pigment-granules.  It  extends 
with  the  retinal  stroma  as  the  pars 
ciliaris  retina,  (see  page  285),  beyond 
the  ora  serrata,  where  the  nervous 
layers  terminate. 

REFRACTING  MEDIA 

The  Aqueous  Humor  (humor  aqueus)  is 
a  clear,  alkaline,  serous  fluid,  composed  of 
water  96.7,  albumen  o.i,  chloride  of  sodium 
and  extractive  matters  3.2,  weighing  4  to  5 
grains,  and  filling  the  anterior  (camera  oculi 
anterior)  and  posterior  aqueous  chambers 
(camera  oculi  posterior)  which  communicate 
with  each  other  when  the  pupil  is  dilated 
sufficiently  to  remove  the  pupillary  margin 
of  the  iris  from  the  surface  of  the  lens. 
The— 

Anterior  Chamber  (camera  oculi  anterior) 
of  the  Eyeball, — has  the  cornea  in  front 
and  the  iris  behind.     The  peripheral 
angle  of  this  chamber  is  called  the  Fil- 
tration Angle  (angulus  iridis). 
Posterior  Chamber  (camera  oculi  posterior)  of  the  Eyeball, — is  a  narrow 
chink  between  the  peripheral  part  of  the  iris,  the  suspensory  ligament 
of  the  lens,  and  the  ciliary  processes. 

The  Vitreous  Body  (corpus  vitreum)  is  a  transparent  jelly-like  sub- 
stance, composed  of  an  albuminous  fluid  enclosed  in  a  delicate  membrane, 


288  HUMAN   ANATOMY 

also  transparent  and  named  the  hyaloid  membrane  (membrana  hyaloidea). 
It  is  apparently  structureless,  has  neither  vessels  nor  nerves,  and  is  situated 
in  the  concavity  of  the  retina,  which  it  fills,  forming  about  Y§  of  the  entire 
globe.  Running  antero-posteriorly  in  its  centre  is  a  canal,  filled  with  fluid, 
and  lined  by  a  prolongation  of  the  hyaloid  membrane,  called  the — 

Canal  of  Stilling  (canalis  hyaloideus), — which  in  the  foetus  conveyed  the 

hyaloid  artery  to  the  membrana  pupillaris.     It  extends  from  the 

entrance  of  the  optic  nerve,  forwards   directly  through  the  centre 

of  the  vitreous  humor  to  the  back  of  the  crystalline  lens. 

Fossa  Patellaris, — is  a  deep  concavity  on  the  front  of  the  vitreous,  for 

the  posterior  convex  surface  of  the  lens. 

Hyaloid  Membrane, — is  the  delicate  capsule  which  encloses  the  vitreous 
humor,  and  has  been  supposed  to  give  off  delicate  septa  into  its  sub- 
stance.    In  front  of  the  ora  serrata  it  is  thickened  and  is  termed  the — 
Zonula  Ciliaris  or  Zonule  of  Zinn, — presents  a  series  of  furrows,  radially 
arranged,  for  the  reception  of  the  ciliary  processes.     It  splits  into  2 
layers,  one  of  which  lines  the  fossa  patellaris,  the  other  is  the — 
Suspensory  Ligament  of  the  Lens, — passes  over  the  ciliary  body  to  be 

attached  to  the  capsule  of  the  lens. 

Canal  of  Petit    (spatia   zonularia), — a   sacculated   canal,   behind   the 
suspensory  ligament,   encircles   the  equator  of   the  lens,   and  lies 
between  the  two  layers  into  which  the  zonule  of  Zinn  is  split. 
The  Crystalline  Lens  (lens  crystallina)  is  a  bi-convex,  elastic,  trans- 
parent body,  enclosed  in  a  capsule,  held  in  place  by  a  suspensory  ligament, 
and   situated  immediately   behind   the   pupil 
and  in  front  of  the  vitreous  body,  in  the  fossa 
patellaris  of  which  its  posterior  and  most  con- 
vex  surface  rests.     The  ciliary  processes  en- 
circle it   and  slightly  overlap  its  margin.     It 
consists  of  concentric  layers  formed  of  minute 
parallel  fibres,  which  are  hexagonal  prisms  with 
dentated    edges   fitting  accurately  into  each 
other.      Faint  lines,  six  or  more  in  number, 
radiate  from  the  anterior  and  posterior  poles 

to  the  circumference  and  correspond  to  the  free  edges  of  septa  in  the 
lens.  The  external  layers  are  soft,  the  deeper  are  firmer,  and  the  central 
ones  form  a  hard  nucleus,  the  nucleus  lentis.  The  lens  is  unorganized, 
having  neither  vessels  nor  nerves,  but  is  nourished  by  imbibition  from 
neighboring  structures,  possibly  from  the  aqueous  humor.  Its — 

Capsule   (capsula  lentis), — is  transparent,   elastic,    iHjooo   incn   thick 
antreiorly,  Hooo  inch  posteriorly;  has  a  layer  of  flat  cells  between  its 


THE    EYE  289 

anterior  portion  and  the  lens,  which,  after  death,  break  down  into  a 
fluid,  the  liquor  morgagni. 

Suspensory  Ligament, — connects  the  capsule  with  the  ciliary  body, 
and  is  the  anterior  of  the  two  layers  formed  by  the  splitting  of  the 
zonule  of  Zinn  (zonula  ciliaris)  (see  p.  287).  It  is  shown  exaggerated 
in  the  cut. 

Canal  of  Petit,  (spatia  zonularia), — is  a  triangular  space  around  the 
circumference  of  the  lens,  formed  by  the  separation  of  the  two  por- 
tions of  the  zonule  of  Zinn  (zonula  ciliaris)  (shown  inflated  in  the  cut). 

MUSCLES  AND  NERVES  OF  THE  EYEBALL 

Muscles  of  the  Eyeball,  are  6  in  number,  4  Recti  and  2  Oblique,  which 
are  inserted  into  the  sclerotic  coat  (tunica  fibrosa),  just  behind  the  margin 
of  the  cornea.     The  insertions  of  the  superior,  inferior,  internal  and  ex- 
ternal  recti  correspond   to   the  ends  of  the  four 
FIG.  92.  ,  .... 

arms  of  an  equal-armed  cross,  imagined  to  exist 

behind  the  corneo-sclerotic  junction.     The  inser- 
tion of  the  superior  oblique  (14)  lies  between  the 
insertions  of  the  superior  and  external  rect,  that 
of  the  inferior  oblique  (13)  somewhat  behind  the 
insertion  of  the  superior  oblique.     These  muscles 
are  described  on  page   76.     The  tendon  of  the 
superior  oblique  passes  through  a  pulley  or  trochlea 
on  the  internal  angular  process  of  the  frontal  bone, 
before  being  inserted  into  the  eyeball:  (see  Fig.  92). 
Nerves  supplying  the  muscles  of  the  eyeball  are  the  3d,  4th  and  6th 
cranial  nerves;  the  3d  supplies  the  superior,  inferior  and  internal  recti 
and  the  inferior  oblique,  the  4th  supplies  the  superior  oblique,  and  the 
6th  supplies  the  external  rectus. 

VESSELS  OF  THE  EYE 

Arteries  supplying  the  eye  and  its  appendages  are, — the  Ophthalmic 
and  Anterior  Cerebral  branches  of  the  internal  carotid  artery;  and  the 
Infra-orbital  branch  of  the  internal  maxillary,  from  the  external  carotid. 
The  Ophthalmic  Artery  arises  from  the  cavernous  portion  of  the  internal 
carotid,  enters  the  optic  foramen  to  the  orbit,  and  gives  off  the  following 
branches  to  the  eye  and  its  appendages: — 

Arteria  Centralis  Retina  (2), — pierces  the  optic  nerve  (i)  obliquely,  and 

is  distributed  to  the  retina. 

Muscular  Branches,  2, — superior  and  inferior,  supply  the  muscles  of 
the  eyeball,  and  give  off  the  anterior  ciliary  (see  below). 


2QO  HUMAN   ANATOMY 

Lacrintal, — to  the  lacrimal  gland,  the  eyelids,  and  the  conjunctiva, 

anastomosing  with  the  palpebral. 
Supra-orbital, — supplies   the    superior    rectus   and   levator   palpebrae 

muscles. 
Internal  Palpebral  (aa.  palpebrales  mediales), — superior  and  inferior, 

— to  the  eyelids. 

Nasal,  (a.  dorsalis  nasi), — to  the  lacrimal  sac,  and  the  nose. 
Short  Ciliary  (aa.  ciliares  posteriores  breves),  6  to  12, — pierce  the  sclerotic 

at  the  lamina  cribrosa,  supplying  the  choroid  and  the  ciliary  processes. 
Long  Ciliary  (aa.  ciliares  posteriores  longag),  2, — pierce  the  sclerotic,  and 

pass  forward  between  it  and  the  choroid,  to  supply  the  iris,  forming 

two  arterial  circles  thereon,  the  circulus  major  at  the  ciliary  border, 

and  the  circulus  minor  near  the  pupillary  margin. 
Anterior  Ciliary  (aa.  ciliares  anteriores)  (3), — arise  from  the  muscular 

branches,  form  a  zone  beneath  the  conjunctiva,  then  pierce  the 

sclerotic,  and  join  the  circulus  major  on  the  iris. 
Anterior  Cerebral,  branch   of   the  Internal    Carotid, — sends   nutrient 

capillaries  to  the  optic  nerve. 
Infra-orbital,  branch  of  the  Internal  Maxillary  artery, — sends  branches 

to  the  inferior  rectus  and  inferior  oblique  muscles,   and  to  the  lac- 
rimal gland. 

Veins  of  the  Eye  are  collected  into  two  main  trunks,  the  Superior  and 
Inferior  Ophthalmic  Veins,  which  empty  into  the  cavernous  sinus,  after 
collecting  the  blood  from  the  smaller  venous  channels  through  the  Vena 
Vorticosa  of  the  choroid.  The  veins  of  the  eye  anastomose  freely  with  the 
facial  veins,  thus  permitting  the  escape  of  venous  blood  in  either  direction. 
Lymph-spaces  of  the  Eye.  The  principal  lymph-spaces  found  in  the 
eyeball  and  its  connected  structures  are  the — • 

Canal  of  Schlemm  (sinus  venosus  sclerae), — around  the  circumference 

of  the  iris. 
Peri-choroidal  Space, — between  the  choroid  and  the  sclerotic  (tunica 

fibrosa). 
Peri-sclerotic   Space, — between   the  sclerotic   (tunica  fibrosa)   and  the 

capsule  of  Tenon  (fascia  bulbi),  is  continuous  with  the  subdural  and 

subarachnoid  spaces. 
Vaginal  Spaces, — have  been  described  as  existing  between  the  sheaths 

of  the  optic  nerve. 

NERVES  OF  THE  EYE 

Nerves  of  the  Eye.     Besides  the  3d,  4th  and  6th  nerves,  already  men- 
tioned as  supplying  the  muscles  of  the  eyeball,  the  eye  is  supplied  with 


THE   EYE 


291 


common  sensation  by  branches  from  the  ophthalmic  division  of  the  5th 
and  the  ophthalmic  ganglion,  also  motor  filaments  from  the  5th,  and  its 
special  sense  of  sight,  from  the  2d  or  optic  nerve.  The — 

Sympathetic  Branches, — arise  from   the   medulla,   and   the  cavernous 
and  carotid  plexuses,  and  join  the  3d,  4th,  5th,  and  6th  nerves,  send- 
ing filaments  to  the  dilator  fibres  of  the  iris,  to  the  muscles  of  the  orbit 
and  lids,  to  the  ophthalmic  ganglion,  and  to  the  walls  of  the  arteries. 
Short  Ciliary, — some   6   to    10  in  number,  arise  from  the  ophthalmic 
ganglion  (see  page  224),  pierce  the  sclerotic  and  go  to  the  ciliary 
muscle,  iris,  cornea,  and  to  the  sheath  of  the  optic  nerve. 
Ascending, — from  Meckel's  (spheno-palatine)  ganglion  (see  page  224). 
enter  the  orbit  by  the  spheno-maxillary  fissure,  going  to  the 'optic 
nerve,  the  6th  nerve,  and  the  ciliary  ganglion. 

FIG.  93. 


CILIARY  GANGLION 


The  Optic  Nerve,  2d  Cranial  (Plate  6,  page  244),  begins  at  the  anterior 
part  of  the  optic  commissure,  passes  into  the  orbit  by  the  optic  foramen 
in  company  with  the  ophthalmic  artery,  is  pierced  by  the  central  artery 
of  the  retina,  and  enters  the  eyeball  posteriorly  %  inch  inwardly  from  its 
axis,  piercing  the  sclerotic  (tunic  fibrosa)  and  choroid  coats,  and  finally 
expanding  in  the  retina.  f  It  is  surrounded  by  a  tubular  process  of  dura 
mater,  which  as  the  nerve  enters  the  orbit,  subdivides  to  form  both  the 
sheath  of  the  nerve  and  the  periosteum  of  the  orbit.  The  two  nerves  are 
connected  together  at  the  commissure,  from  the  back  of  which  most  of 
their  fibres  may  be  traced  through  the  optic  tracts  to  the  lower  visual  centres 


2Q2  HUMAN    ANATOMY 

of  the  brain,  viz. — the  external  (lateral)  geniculate  body,  the  upper 
quadrigeminal  body,  (colliculus  superior),  and  the  pulvinar  of  the  optic 
thalamus. 

The  Optic  Commissure  or  Chiasma  (Plate  6,  page  244),  is  seen  at  the 
base  of  the  brain  in  front  of  the  tuber  cinereum  and  behind  the  lamina 
cinerea.  It  contains  four  sets  of  fibres,  one  of  which  decussates  in  the 
commissure  with  its  fellow  set  of  the  opposite  side.  The  four  sets  of 
fibres  are  arranged  in  the  following  manner: — 

Crossed  or  Decussating  Fibres  (i), — are  the  most  numerous;  lying  in  the 
centre  of  the  commissure,  they  pass  from  the  optic  tract  of  one  side 
to  the  optic  nerve  of  the  other  side,  con- 
necting the  retina  of  each  eye  with  the  op-  FlG* 
posite  hemisphere  of  the  brain. 
Uncrossed  or  Longitudinal  Fibres  (2), — occupy 
the   outer   sides    of   the   commissure   and 
tracts,  passing  from  the  tracts  to  the  nerves 
of  the  same  sides,  and  connecting  the  tem- 
poral side  of  each  retina  with  the  cerebral 
hemisphere  of  its  own  side. 

Inter-retinal  Fibres  (3), — in  the  anterior  portion  of  the  commissure, 
pass  from  one  optic  nerve  to  the  other,  connecting  the  nasal  sides  of 
the  retinas  of  both  eyes  with  each  other. 

Commissural  Fibres  (4)  or  Commissure  of  Gudden, — in  the  posterior  por- 
tion of  the  commissure,  have  nothing  to  do  with  vision,  but  pass  from 
one  internal  (medial)  geniculate  body  to  the  other,  or  to  the  op- 
posite posterior  quadrigeminal  body  (colliculus  inferior)  (Whitaker). 

The  Optic  Tract  arises  from  the  brain  by  two  bands,  an  external  and  an 
internal.  The  external  (lateral)  band  arises  from  the  external  (lateral) 
geniculate  body,  the  upper  quadrigeminal  body  (colliculus  superior)  and 
the  pulvinar  of  the  optic  thalamus,  the  lower  visual  centres.  The  internal 
(medial)  band  arises  from  the  internal  (medial)  geniculate  body  and  the 
inferior  quadrigeminal  body  (colliculus  inferior),  most  of  its  fibres  being 
commissural  between  the  two  internal  (medial)  geniculates.  The  two 
bands  wind  around  the  crus  (cerebral  peduncle)  and  join  together  opposite 
its  centre  in  a  flattened  band,  which  becomes  cylindrical  and  continues  on 
to  connect  with  the  tract  of  the  opposite  side  in  the  optic  commissure. 
In  its  course  the  tract  is  attached  to  the  surface  of  the  crus  by  its  anterior 
margin,  and  receives  some  fibres  from  the  tuber  cinereum  and  the  lamina 
cinerea  (lamina  terminalis). 

Meynert's  Commissure  (fasciculus  retroflexus), — consists  of  the  fibres 


THE   EYE  293 

from  the  epithalamic  habenular  nucleus,  which  cross  in  the  optic 

commissure  and  enter  the  crus  (cerebral  peduncle)  on  the  opposite 

side,  passing  obliquely  through  the  red  nucleus  into  the  hypothalamic 

nucleus.     It  is  concerned  with  olfactory  impulses. 

Visual  Centres  in  the  Brain.     The  lower  visual  centres  are  the  external 

(lateral)    geniculate    body,    the    upper   quadrigeminal    body    (colliculus 

superior),  and  the  pulvinar  of  the  optic  thalamus,  to  which  the  optic 

nerve  fibres  are  traced.     From  these  nuclei  other  fibres  go  to  the  cortical 

visual  centre,  which  is  located  in  the  cuneus  of  the  occipital  lobe,  and 

probably  also  in  the  adjacent  lingual  lobule  of  the  temporal  lobe, 

APPENDAGES  OF  THE  EYE 

The  Tutamina  Oculi  (organa  oculi  accessoria)  or  appendages  of  the  eye, 
include  the  eyebrows,  the  eyelids,  the  conjunctiva,  the  lacrimal  gland,  the 
lacrimal  sac,  and  the  nasal  duct  (ductus  naso-lacrimalis). 

The  Eyebrows,  or  Supercilia,  are  two  arched  eminences  of  thickened 
integument  over  the  supra-orbital  arches,  and  connected  beneath  with  the 
orbicularis  palpebrarum,  corrugator  supercilii  and  occipito-frontalis  mus- 
cles. They  are  covered  with  short,  thick  hairs,  and  are  drawn  downward 
and  inward  by  the  corrugator  supercilii:  (see  page  75). 

The  Eyelids,  or  Palpebrae,  are  two  thin,  movable  folds,  placed  in  front 
of  the  eye,  for  its  protection.  The  upper  lid  is  the  more  movable  one, 
having  its  own  levator  muscle,  the  levator  palpebrae  superioris.  They  are 
composed  externally  of  skin,  internally  of  mucous  membrane  (the  palpebral 
conjunctiva),  and  between  these  lie  areolar  tissue,  the  orbicularis  muscle, 
tarsal  cartilage,  fibrous  membrane,  Meibomian  glands  (glandulae  tarsales), 
vessels  and  nerves.  The  upper  lid  has,  in  addition,  the  aponeurosis  of 
the  levator  palpebrae. 

Eyelashes,  or  Cilia, — are  a  double  or  triple  row  of  short  hairs,  situated 
on  the  free  margins  of  the  lids;  their  follicles  lying  in  the  connective 
tissue  beneath  the  tarsal  cartilages. 

Glands  of  Moll  (glandulae  ciliares), — are  enlarged  and  modified  sweat- 
glands,  the  openings  of  which  are  in  several  rows,  near  the  attachment 
of  the  eyelashes. 

Palpebral  Fissure  (rima  palpebrarum), — is  the  space  between  the  free 
margin  of  the  lids,  its  outer  and  inner  angles  being  termed  respect- 
ively the  external  (commissura  palpebrarum  lateralis)  and  internal 
(commissura  palpebrarum  medialis)  canthus. 

Lacus  Lacrimalis, — is  a  small  triangular  space  at  the  internal  canthus, 
between  the  lids  and  the  globe. 


294  HUMAN   ANATOMY 

Lacrimal  Papilla, — on  the  edge  of  each  lid,  about  34  inch  from  the 
internal  canthus. 

Punctum  Lacrimale, — a  minute  orifice  on  each  papilla,  and  the  beginning 
of  the  lacrimal  canal. 

Tar  sal  Plates  (tarsi), — are  two  thin,  elongated  plates  of  dense  connect- 
ive tissue,  about  an  inch  in  length,  placed  one  in  each  lid,  giving  it 
form  and  support.  The  upper  one  is  crescentic  in  shape,  the  lower 
one  is  elliptical  and  smaller. 

Tar  sal  Ligaments,  external  (ligamentum  palpebralis  laterale), — con- 
nects the  outer  angle  of  the  tarsal  plate  to  the  malar  bone.  The 
internal  (ligamentum  palpebralis  mediale)  connects  the  inner  angle 
of  the  plate  to  the  nasal  process  of  the  maxilla.  The  internal  one 
is  often  called  the  tendo  oculi. 

Meibomian  Glands  (glandulae  tarsales)  (i), — are  sebaceous  glands  em- 
bedded in  grooves  in  the  inner  surface  of  the  tarsal  plates,  about  30 
in  the  upper  eyelid,  less  in  the  lower 
one.     Their  ducts  open  on  the  inner  FlG-  95- 

edge  of  the  free  margin  of  the  lids 
by  minute  foramina,  through  which 
their  secretion  is  furnished  to  pre- 
vent the  lids  adhering  to  each 
other. 

Muscles, — the  palpebral  portion  of  the 
orbicularis  muscle  is  very  thin  and 
pale;  the  tensor  tarsi  compresses 
the  punctum  lacrimale  and  the 
lacrimal  sac:  (see  page  75). 

Arteries, — are  the  palpebral  branches  of  the  ophthalmic  artery,  forming 
the  superior  and  inferior  tarsal  arches,  and  anastomosing  with  the 
orbital  branch  of  the  temporal,  the  lacrimal,  transverse  facial,  and 
angular  arteries. 

Nerves y — the  3d,  facial,  and  sympathetic  to  the  muscles;  the  5th  to  the 
skin  and  conjunctiva. 

The  Conjunctiva  (Tunica  Conjunctiva)  is  the  mucous  membrane  lining 
the  inner  surface  of  the  eyelids,  and  reflected  over  the  front  of  the  sclerotic 
and  cornea.  It  is  continuous  with  the  mucous  lining  of  the  Meibomian 
glands  (glandulae  tarsales),  lacrimal  ducts,  lacrimal  sac,naso-lacrimal  duct, 
duct  and  lacrimal  gland.  The — 

Palpebral  Conjunctiva  (tunica  conjunctiva  palpebrarum), — consists  of 
connective  tissue  covered  by  epithelium,  is  traversed  by  furrows,  and 
has  papillae,  follicular  glands,  and  lymphoid  tissue. 


THE   EYE 


295 


Ocular  Conjunctiva  (tunica  conjunctiva  bulbi), — is  very  thin  and 
transparent,  loosely  attached  on  the  sclerotic,  firmly  adherent  over 
the  cornea,  where  it  has  no  vessels  in  its  structure.  It  has  very  few 
papillae,  and  no  glands. 

Palpebral  Folds,  superior  and  inferior, — are  where  the  conjunctiva  is 
reflected  over  the  globe,  the  fornix  conjunctiva  lying  between  them, 
and  containing  mucous  glands  and  trachoma  glands,  the  latter  being 
analogous  to  lymphoid  follicles. 

Plica  Semilunaris,  or  Semi-lunar  Fold, — a  crescentic  fold  of  conjunctiva 
at  the  inner  canthus,  considered  to  be  the  rudiment  of  the  membrana 
nidi  tans  or  3d  eyelid  of  birds. 

Caruncula  lacrimalis, — is  a  small,  red,  conical  body,  situated  in  the 
lacus  lacrimalis,  at  the  inner  canthus  of  the  eye;  consisting  of  a  small 
island  of  skin,  containing  sebaceous  and  sweat  glands,  and  a  few 
slender  hairs.  It  is  the  source  of  the  whitish  secretion  which  collects 
at  the  inner  angle  of  the  eye.  It  is  connected  by  tendinous  fibres  to 
the  capsule  (fascia  bulbi)  of  Tenon  and  to  the  rectusinternus  muscle. 

The  Lacrimal  Gland  (i)  is  an  oval  gland  situated  in  a  depression  on 
the  orbital  portion  of  the  frontal  bone,  at  the  outer  angle  of  the  orbit,  its 

inferior  surface  resting  on  the  eyeball, 
its  lower  margin  or  lobe  being  covered 
by  conjunctiva.  Its  front  portion  is 
separated  from  the  rest  of  the  gland 
by  a  fibrous  septum,  and  is  called  the 
accessory  gland  of  Rosenmiillcr  (glandula 
lacrimalis  inferior).  Its  ducts,  from  6 
to  12  in  number,  open  by  a  row  of 
orifices  on  the  upper  and  outer  por- 
tion of  the  palpebral  conjunctiva.  Its 
secretion,  the  tears,  lubricates  the  sur- 
face of  the  eyeball;  the  excess  evapo- 
rating or  being  collected  in  the  lacus, 
from  which  it  passes  through  the 
puncta  (2)  into  the  canaliculi  (3)  and 
the  lacrimal  sac  (4),  and  thence  by  the  naso-lacrimal  duct  (5)  to  the 
inferior  meatus  of  the  nose. 

The  Canaliculi  (3)  or  lacrimal  canals  are  two  minute  canals,  ^5  inch 
in  diameter  and  Y$  inch  long,  which  extend  from  the  punctum  (2)  in  each 
lid  to  the  lacrimal  sac  (4).  They  are  lined  with  mucous  membrane, 
and  enveloped  by  fibres  of  the  tensor  tarsi  muscle. 


FIG.  96. 


296  HUMAN   ANATOMY 

The  Lacrimal  Sac  (4)  is  the  superior  dilated  extremity  of  the  nasal 
duct  (5),  and  is  situated  in  the  groove  formed  by  the  lacrimal  bone  and 
the  nasal  process  of  the  maxilla.  Its  form  is  oval,  flattened  antero- 
posteriorly;  its  dimensions  about  %  inch  long  and  %  inch  wide.  Its 
fundus  is  crossed  by  the  tarsal  ligament,  and  by  the  tensor  tarsi  muscle. 
Its  junction  with  the  nasal  duct  may  be  interrupted  by  folds  of  the  lining 
mucous  membrane. 

The  Nasal  Duct  (ductus  naso-lacrimalis)  (5)  is  a  membranous  canal 
extending  from  the  lacrimal  sac  to  the  inferior  meatus  of  the  nose.  It  is 
about  %  inch  long,  ^  inch  in  diameter,  is  contained  in  the  osseous 
lacrimal  canal,  curving  downward,  backward  and  outward,  and  its 
calibre  is  narrowest  about  its  middle.  Its  mucous  lining  is  thick,  and 
continuous  with  the  Schneiderian  membrane  of  the  nasal  cavity.  The — 

Valve  of  Hamer  (plica  lacrimalis), — is  an  imperfect  valve  at  the  terminal 
'  orifice  (6)  of  the  naso-lacrimal  duct,  and  is  formed  by  a  fold  of 
mucous  membrane. 

THE  EAR  (AURIS  OR  ORGANON  AUDITUS) 

The  Organ  of  Hearing  is  divisible  into  3  parts — the  external  ear  (auris 
externa),  the  middle  ear  (auris  media)  or  tympanum,  and  the  internal  ear 
or  labyrinth  (auris  interna) ;  which  are  situated  in  or  upon  the  mastoid 
and  petrous  portions  of  the  temporal  bone  (described  on  page  20): 
The— 

External  Ear  (auris  externa), — consists  of  the  auricle  or  pinna,  and 
the  auditory  canal  (meatus  acusticus  externus),  which  extends  to 
the  membrana  tympani. 

Middle  Ear  or  Tympanum  (auris  media), — consists  of  the  atrium  or 
tympanic  cavity  proper  (cavum  tympani),  and  the  attic  or  epitym- 
panic  recess;  it  contains  the  membrana  tympani,  the  ossicles  of  the 
tympanum  (ossicula  auditus)  and  the  tympanic  orifice  of  the  Eus- 
tachian  tube  (tuba  auditiva). 

Internal  Ear  or  Labyrinth  (auris  interna), — consists  of  the  osseous 
labyrinth  (labyrinthus  osseus)  and  the  membranous  labyrinth 
(labyrinthus  membranaceus),  the  latter  being  contained  within  the 
former,  which  comprises  the  vestibule  (vestibulum),  the  semicircular 
canals  (canales  semicirculares  ossei),  and  the  cochlea.  The  mem- 
branous labyrinth  (labyrinthus  membranaceus)  consists  of  the  utricle 
(utriculus),  the  saccule  (sacculus),  and  the  membranous  semicircular 
canals  (ductus  semicirculares),  and  contains  the  terminal  filaments 
of  the  auditory  nerve  (n.  acusticus). 


THE    EAR  297 

THE  EXTERNAL  EAR  (AURIS  EXTERNA) 

The  Auricle  or  Pinna  (auricula)  is  the  external  irregularly  shaped 
appendage,  fastened  to  the  malar  and  temporal  bones  by  ligaments.  It 
consists  of  a  thin  plate  of  yellow  fibro-cartilage,  deficient  in  places  where 
its  parts  are  joined  together  by  fibrous  tissue,  and  is  covered  by  peri- 
chondrium  and  integument,  the  latter  containing  sebaceous  and  sweat 
glands,  and  provided  with  short,  downy  hairs.  The  Auricle  presents 
several  elevations  and  depressions,  which  are  due  to  the  folding  of  its 
cartilage,  and  are  named  as  follows: — 

Helix, — the  outer  curved  edge  of  the  pinna,  beneath  which  is  a  deep 

groove,  the  fossa  navicularis  (scapha)  or  fossa  of  the  helix. 
Anti-helix, — a  curved  ridge,  parallel  with  and  in  front  of  the  helix,  bifur- 
cating above  forming  the  crura  antihelicis  which  enclose  a  triangular 
depression,  the  fossa  triangularis  auriculae. 
Concha  Auricula, — the  central  cavity  leading  into  the  auditory  canal 

(meatus  acusticus  externus). 
Tragus,-^-&  conical  eminence  in  front  of  the  concha,  usually  covered 

with  hair  along  its  inferior  border. 
Anti-tragus, — a  smaller  projection  facing  the  tragus,  from  which  it  is 

separated  by  a  deep  fissure,  the  incisura  intertragica. 
Tubercle  (tuberculum  auricula}  of  Darwin, — a  small  tubercle  frequently 

seen,  where  the  helix  turns  downward. 
Lobe  or  Lobule   Auricula, — the  soft,  pendulous   portion,  composed  of 

integumentary,  adipose  and  connective  tissues. 

Muscles  of  the  Auricle.     The  extrinsic  muscles  are  the  Attollens, 
Attrahens  and  Retrahens  Auriculam,  described  on  page  75.     The  intrinsic 
muscles  are  very  slightly  developed  (see  page  79)  and  are  the — 
/•     Musculus  Hdicis  Major, — vertically  on  the  anterior  border  of  the  helix. 
^_  Musculus  Helicis  Minor, — on  the  lateral  surface  of  the  root  of  the  helix. 
Musculus  Tragicus, — lies  vertically  on  the  outer  surface  of  the  tragus. 
Musculus  Anti-tragicus, — on  the^posterior  wall  of  the  auditory  canal. 
Musculus  Transversus  Auricula, — on  the  posterior  surface  of  the  auricle, 

radiating  outward  from  the  convexity  of  the  concha. 
Musculus  Obliquus  Auricula, — also  on  the  posterior  surface,  radiating 

upward  from  the  convexity  of  the  concha. 

The  Auditory  Canal  (meatus  acusticus  externus)  is  an  osseo-cartilaginous 
tube,  about  i  finches  long,  extending  from  the  concha  to  the  membrana 
tympani,  and  curved  irregularly  in  its  course.  The  cartilaginous,  or 
external  portion,  is  about  ^  inch  long,  and  deficient  posteriorly  and  above, 
where  it  is  filled  by  strong  fibrous  tissue.  The  canal  is  lined  with  integu- 


298  HUMAN   ANATOMY 

ment,  having  numerous  hair  follicles,  sebaceous  and  ceruminous  glands. 
Its  relations  are — in  front,  the  condyle  of  the  lower  jaw;  below  and  in  front, 
the  parotid  gland;  behind,  the  mastoid  cells  and  the  lateral  sinus, 
separated  from  it  by  a  very  thin  bony  plate;  above,  the  mastoid  cells  and 
the  dura  mater  of  the  brain,  separated  from  it  by  a  thin  osseous  plate. 
The— 

Sulcus  Tympanicus, — is  a  circumferential  groove  at  the  bottom  of  the 

canal  for  the  insertion  of  the  membrana  tympani.     It  is  interrupted 

above  by  a  notch,  the  incisura  Rivinii. 

Vessels  and  Nerves.  The  Arteries  of  the  auricle  are  derived  from  the 
external  carotid  artery,  viz. — the  anterior  and  posterior  auricular,  and  the 
auricular  branch  of  the  occipital.  Those  of  the  auditory  canal  are 
branches  from  the  posterior  auricular,  internal  maxillary,  and  temporal 
arteries.  The  Nerves  of  the  canal  are  derived  from  the  temporo-auricular 
branch  of  the  maxillary  division  of  the  5th,  and  the  auricular  branch  of  the 
Vagus.  Those  of  the  auricle  are  the — 

Auricularis  Magnus, — from  the  cervical  plexus. 

Auricular, — branch  of  the  vagus  (also  called  Arnold's  nerve). 

Auriculo-iemporal,  branch  of  the  mandibular  div.  of  the  5th. 

Occipitalis  Major, — from  the  post,  division  of  the  2nd  cervical  nerve. 

Occipitalis  Minor,' — from  the  cervical  plexus. 

Posterior  Auricular, — branch  of  the  facial,  to  the  muscles. 

THE  MEMBRANA  TYMPANI 

The  Membrana  Tympani,  or  Drumhead,  is  an  oval,  inelastic,  semi- 
transparent  membrane,  about  ^50  inch  in  thickness,  situated  obliquely 
at  the  bottom  of  the  auditory  canal,  inclined  inward  and  forward,  so  as  to 
form  almost  a  continuation  of  the  posterior  wall  of  the  canal.  As  seen 
through  the  canal,  it  is  of  a  delicate  blue-gray  color,  arched  inward,  and 
presents  for  consideration  the  following  points: — 

Malleolar  Eminence, — white  in  color  at  the  upper  border,  made  by  the 

short  process  of  the  malleus  behind. 
Malleolar  Stripe, — also  white,  running  downward  from  the  eminence  and 

formed  by  the  handle  of  the  malleus  behind. 

Light-spot, — a  triangular  reflection,  its  apex  at  the  tip  of  the  malleus 
handle,  its  base  extending  to  the  periphery  of  the  membrane.     It  is 
due  to  the  concavity  of  the  exterior  surface  of  the  membrane. 
Umbo,  or  Navel, — is  the  dark,  central,  depressed  part  of  the  membrane. 
ShrapnelVs  Membrane  (pars  flaccida), — is  the  upper  posterior  part  of 
the  drumhead,  where  it  is  somewhat  flaccid. 


THE   EAR 


2Q9 


Structure.     The  Membrana  Tympani  is  composed  of  3  layers,  an  ex- 
ternal or  cuticular  layer  (stratum  cutaneum),  a  middle  or  fibrous  (mem- 
brana  propria),  and  an  internal  or  mucous  layer  (stratum  mucosum). 
Its   circumference  is   thickened   to   form   an   incomplete   ring    (annulus 
fibrocartilagineus),  which  is  received  into  the  sulcus  tympanicus  at  the 
inner  end  of  the  auditory  canal.     The  anterior  and 
posterior  ends  of  this  ring  are  shown  by  (z>)  and  (h) 
in  the  figure.     The — 

External  or  Cuticular  Layer  (stratum  cutaneum), — 
is  derived  from  the  integument  lining  the  audi- 
tory canal  (meatus  acusticus  externus). 
Middle    or  Fibrous  Layer  (membrana  propria), — 
consists  of  an  outer  layer  of  fibres  which  radiate 
from  the  handle  of  the  malleus;  and  an  inner 
layer  of  circular  fibres,  most  numerous  around  the  circumference. 
Between  these  two  sets  of  fibres  are  situated  the  short  process  and 
handle  of  the  malleus. 
Internal  or  Mucous  Layer  (stratum  mucosum), — is  continuous  with  the 

mucous  lining  of  the  tympanum. 

The  Internal  Surface  of  the  Membrana  Tympani  is  convex,  and  presents 
the  curved  handle  of  the  malleus  pointing  downward  between  its  layers, 
also  the  chorda  tympani  nerve  passing  along  the  upper  margin  to  the  iter 
chordae  anterius  in  the  Glaserian  (tympano-squamous)  fissure. 

Nerves  and  Vessels.  The  Membrana  Tympani  receives  its  nervous 
supply  from  the  auriculo-temporal  branch  of  the  mandibular,  the  auricular 
branch  of  the  vagus  and  the  tympanic  branch  of  the  glosso-pharyngeal. 
The  Veins  open  into  the  external  jugular,  except  those  on  the  inner  surface, 
which  drain  partly  into  the  lateral  sinus  and  veins  of  the  dura  mater,  and 
partly  into  a  plexus  on  the  Eustachian  tube  (tuba  auditiva).  The 
Arteries  are  the — 

Deep  A  uricular,  branch  of  the  internal  maxillary, — supplies  the  external 
layer,  and  forms  with  the  tympanic  branches  a  capillary  plexus  in  the 
middle  layer. 

Tympanic  Branches,  of  the  internal  maxillary  and  internal  carotid  arte- 
ries,— supply  the  internal  layer,  the  former  with  the  stylo-mastoid 
artery  forming  a  vascular  circle  around  the  membrane,  and  both 
anastomosing  on  the  membrane  with  the — 
Vidian  (a.  canalis  pterygoidea), — branch  of  the  internal  maxillary,  and 

the— 

Stylo-mastoid, — from  the  posterior  auricular  branch  of  the  external 
carotid. 


3OO  HUMAN   ANATOMY 

THE  MIDDLE  EAR  OR  TYMPANUM  (AURIS  MEDIA) 
The  Tympanum,  or  Drum  (auris  media),  is  an  irregular  cavity  within 
the  petrous  portion  of  the  temporal  bone,  lying  between  the  membrana 
tympani  and  the  tympanic  surface  of  the  petrous  bone  and  communicating 
with  the  naso-pharynx  by  the  Eustachian  tube  (tuba  auditiva).  It 
contains  the  ossicles  (ossicula  auditus)  of  the  tympanum,  part  of  the 
chorda  tympani  nerve,  and  air.  Its  average  diameters  are  about  %  inch 
antero-posteriorly,  ^  to  %  inch  vertically,  and  3-f  2  to  ^  inch  transversely. 
It  consists  of  two  parts,  the  atrium  or  tympanic  cavity  proper  (cavum 
tympani),  opposite  the  tympanic  membrane;  and  the-fl&ix;  or  epitympanic 
recess  above,  containing  the  upper  half  of  the  malleus  and  the  greater  part 
of  the  incus.  Its  roof  and  floor  are  formed  by  thin  osseous  laminae,  the 
floor  separating  it  from  the  jugular  fossa  and  vein,  and  presenting,  near 
the  inner  wall,  a  small  aperture  for,  Jacol 'son's  nerve  (tympanic  branch  of 
the  glosso-pharyngeal).  The  other  walls  cf  the  tympanum  present  for 
examination  the  following  points: — 

OUTER    WALL    (paries    membranacea), — is   formed    by    the    membrana 
tympani  and  presents  the — 

Her  Chorda  Posterius, — opens  close  to  the  posterior  edge  of  the  drum- 
head, for  the  passage  of  the  chorda  tympani  nerve. 
Her  Chorda  Anterius  (canal  of  Huguier), — opens  just  in  front  of  the 

drumhead,  for  the  passage  of  the  chorda  tympani  nerve. 
Glaserian  (tympano-squamous)  Fissure, — opens  above  and  in  front  of 
the  drumhead,   receiving    the  long    process   (processus  gracilis  or 
anterior)  of  the  malleus,  the  anterior  ligament  of  the  malleus,  (laxator 
tympani  tendon)  and  the  tympanic  branch  of  the  internal  maxillary 
artery. 

INNER  WALL  (paries  labyrinthica), — is  the  outer  wall  of  the  labyrinth, 
presents  the — 

Fenestra  Vestibuli  or  Ovalis, — an  oval  opening,  leading  into  the  vestibule, 
and  closed  by  a  membrane,  to  which  is  attached  the  base  of  the  stapes. 
Fenestra  Cochlea   or  Rotunda, — a  smaller  opening,  below  the  fenestra 
vestibuli,  leading  into  the  scala  tympani  of  the  cochlea,  and  closed  by 
the  membrana  tympani  secundaria,  a  membrane  of  3  layers. 
Promontory, — an  elevation  corresponding  to  the  first  turn  of  the  cochlea, 
situated  between  the  fenestras  and  in  front  of  them.     It  is  grooved  by 
the  tympanic  plexus. 

Ridge  of  the  Aquceductus  Fallopii  (prominentia  canalis  facialis), — above 
the  fenestra  vestibuli,  behind  which  it  curves  downward  along  the 
posterior  wall. 

POSTERIOR  WALL  (paries  mastoidea),  separates  it  from  the  mastoid  cells, 
and  presents  the — 


THE    EAR  301 

Opening  of  the  Tympanic  or  Mastoid  Antrum, — which  in  turn  com- 
municates with  the  mastoid  cells. 

Pyramid  (eminentia  pyramidalis), — a  hollow  conical  eminence,  behind 
the  fenestra  vestibuli,  contains  the  stapedius  muscle,  and  a  minute 
canal  communicating  with  the  aquaeductus  Fallopii  (canalis  facialis) 
and  transmitting  a  nerve  to  the  stapedius. 

ANTERIOR  WALL  (paries  carotica),  separates  it  from  the  carotid  canal, 
and  presents  the — 

Opening  of  Canal  (semicanalis  m.  tensoris  tympani)  for  the  Tensor 
Tympani  Muscle, — above,  situated  on  a  small  projection,  sometimes 
called  the  anterior  pyramid. 

Opening  of  the  Eusiachian  Tube  (semicanalis  tubae  auditivae), — next 
below,  the  two  canals  being  separated  from  each  other  by  a  thin, 
horizontal,  bony  plate,  the  processus  cochleariformis  (septum  canalis 
musculotubarii) . 

The  Ossicles  (ossicula  auditus)  of  the  Tympanum  are  three  small  bones, 
which  form  a  chain  across  the  tympanic  cavity,  connecting  the  mem- 
brana  tympani  with  the  fenestra  vestibuli,  and  named  the — • 

Malleus,  or  Hammer  (A), — consists  of  a  head,  neck,  short  process 
(processus  lateralis),  long  process  or  processus  gracilis  (processus 
anterior),  and  handle  or  manubrium.  The 
short  process  and  handle  are  fastened  to  the 
middle  layer  of  the  drumhead.  The  long 
process  (never  found  in  adults)  is  received 
into  the  Glaserian  (tympano-squamous) 
fissure,  and  the  head  articulates  with  the 
head  of  the  incus. 

Incus,  or  Anvil  (B), — resembles  a  two-pronged 
tooth;  it  has  a  head,  also  a  long  and  a  short 
process.  The  head  articulates  with  the  head 
of  the  malleus,  the  short  process  with  the  fossa  incudis  in  the  epitym- 
panic  recess,  the  long  process  with  the  head  of  the  stapes,  by  the 
os  orbictdare,  its  convex  extremity. 

Stapej,.or  Stirrup  (C), — presents  a  head,  neck,  base  and  two  crura.  Its 
head  articulates  with  the  incus,  its  base  rests  on  the  membrane  clos- 
ing the  fenestra  vestibuli,  its  neck  receives  the  tendon  of  the  stapedius 
muscle. 

Ligaments  of  the  Ossicles  are  5  in  number,  besides  the  capsular 
ligaments  of  their  articulations,  3  for  the  malleus,  i  for  the  incus,  and  i 
for  the  stapes,  as  follows: — 


3O2  HUMAN    ANATOMY 

Anterior  Ligament  of  the  Malleus, — is  the  degenerated  laxator  tympani 
muscle,  from  the  neck  of  the  malleus  through  the  tympano-squamous 
fissure  or  its  petro-tympanic  subdivision  to  the  base  of  the  alar 
spine  of  the  sphenoid.  It  is  an  active  muscle  in  most  infants  and 
about  75  per  cent,  of  adults. 

Superior  of  the  Malleus, — from  the  head  of  the  malleus  to  the  roof  of  the 
epitympanic  recess. 

External  of  the  Malleus, — from  the  short  process  of  the  malleus  to  the 
posterior  part  of  the  notch  in  the  tympanic  ring. 

Posterior  of  the  Incus, — from  the  end  of  the  short  process  of  the  incus 
to  the  posterior  part  of  the  epitympanic  recess.  [The  so-called  supe- 
rior ligament  of  the  incus  is  merely  a  fold  of  mucous  membrane.] 

Annular  Ligament  of  tfte  Stapes  (ligamentum  annulare  baseos  stapedis), 
— around  the  circumference  of  the  base  of  the  stapes,  connecting  it 
to  the  margin  of  the  fenestra  vestibuli. 

Muscles  of  the  Tympanum  are  2,  the  Tensor  Tympani  Stapedius 
and  the  laxator  tympani. 

Tensor  Tympani, — arises  from  the  under  surface  of  the  petrous  portion 
of  the  temporal  bone,  the  cartilaginous  Eustachian  tube  (pars  car- 
tilaginea  tubae  auditivae),  and  its  own  osseous  canal  (semicanalis 
m.  tensoris  tympani);  and  is  inserted  into  the  handle  of  the  malleus. 
It  draws  the  membrana  tympani  inward  and  tense.  Its  nerve  is  a 
branch  from  the  trigeminal,  through  the  otic  ganglion. 

Stapedius, — arises  from  a  conical  cavity  in  the  interior  of  the  pyramid; 
its  tendon  emerges  from  the  orifice  at  the  apex  of  the  pyramid,  and 
is  inserted  into  the  neck  of  the  stapes.  It  draws  the  head  of  the  stapes 
backward,  and  probably  compresses  the  contents  of  the  vestibule. 
Its  nerve  is  the  tympanic  branch  of  the  facial. 

Laxator  Tympani, — see  anterior  ligament  of  malleus  (see  page  80). 

Vessels  of  the  Tympanum.  The  Veins  terminate  in  the  pterygoid 
plexus  and  in  the  superior  petrosal  sinus.  The  Arteries  are  6 in  number, 
as  follows: — 

Tympanic, — branch  of  the  internal  maxillary,  entering  by  the  petro 

tympanic  fissure,  anastomosing  on  the  membrana  tympani,   in  a 

vascular  circle  with  the  Stylo-mastoid  and  Vidian  arteries,  and  the 

Tympanic  br.  of  the  internal  carotid. 
Stylo-mastoid, — br.  of  the  posterior  auricular  br.  of  the  external  carotid 

entering  at  the  stylo-mastoid  foramen. 

Petrosal; — br.  of  middle  meningeal  artery,  entering  by  the  hiatus  Fallopii. 
Tympanic, — br.  from  the  internal  carotid  artery. 


THE    EAR  303 

Branch  from  tJie  Ascending  Pharyngeal,-^irom  the  external  carotid;  also 
accompanying  the  Eustachian  tube. 

Nerves  of  the  Tympanum.  Besides  the  nerves  supplying  the  two 
muscles  (see  above),  the  Chorda  Tympani  Nerve  enters  the  tympanum 
by  the  iter  chordae  posterius,  crosses  the  cavity  between  the  handle 
of  the  malleus  and  the  long  process  of  the  incus,  and  makes  its  exit 
by  the  iter  chordae  anterius,  after  passing  close  along  the  upper  part 
of  the  membrana  tympani.  The  mucous  membrane  lining  the 
tympanum  is  supplied  by  the  branches  of  distribution  of  the  Tympanic 
Plexus,  which  lies  on  the  inner  wall  around  the  promontory,  and  is 
formed  by  the — 

Tympanic  Branch  of  the  Glosso-pharyngeal, — also  known  as  Jacobson's 
nerve,  enters  by  an  aperture  in  the  floor  near  the  inner  wall. 

Small  Deep  Petrosal, — from  the  carotid  plexus  of  the  sympathetic,  enters 
from  the  carotid  canal. 

Small  Superficial  Pelrosal, — from  the  otic  ganglion,  enters  near  the  canal 
for  the  tensor  tympani  muscle. 

Branch  from  the  Great  Superficial  Pelrosal, — enters  through  the  inner 
wall,  just  in  front  of  the  fenestra  vestibuli. 

The  Eustachian  or  Auditory   Tube  (tuba   auditiva)  is  an  osseo-car- 

tilaginous  canal,  about  i%  inches  long,  ^2  to  ^3  inch  in  diameter,  which 
forms  a  channel  of  communication  between  the  tympanum  and  the  pharynx. 
It  passes  obliquely  downward,  forward  and  inward,  from  the  anterior 
wall  of  the  tympanum  to  the  naso-pharynx,  where  it  ends  in  an  oval  orifice 
on  the  side  wall  of  the  pharynx  just  behind  the  inferior  meatus  of  the  nose. 
The  osseous  part  (pars  ossea  tubae  auditivae),  ^  inch  long,  terminates 
at  the  retiring  angle  of  junction  of  the  petrous  and  squamous  portions 
of  the  temporal  bone,  in  a  jagged  margin,  to  which  the  cartilaginous  part 
(pars  cartilaginea  tubae  auditivae)  is  attached.  The  latter,  i  inch  long, 
is  formed  by  a  triangular  plate  of  elastic  fibro-cartilage,  folded  on  itself 
above  so  as  to  leave  a  deficiency  below,  which  is  filled  by  fibrous  tissue. 
This  portion  of  the  tube  expands  as  it  descends  into  a  trumpet-shaped 
lower  extremity.  The  tube  is  lined  by  ciliated  mucous  membrane,  con- 
tinuous with  that  of  the  tympanum  and  pharynx,  and  containing  mucous 
glands,  also  adenoid  tissue  near  its  lower  end.  The — 

Tube-tonsil  of  Gerlach, — is  formed  by  the  adenoid  tissue  in  the  mucous 
lining  near  the  pharyngeal  orifice. 

Isthmus, — is  the  narrowest  part  of  the  tube,  at  the  junction  of  the 
osseous  and  cartilaginous  portions. 

Muscles, — are  the  dilator  tubae  fibres  of  the  tensor  palati  (m.  tensor 


304  HUMAN    ANATOMY 

veli  palatini),  which  open  the  tube  during  deglutition,  aided  by  the 
salpingo-pharyngeus  when  present.  The  levator  palati  closes  the 
pharyngeal  orifice.  For  these  muscles  see  page  80. 

Arteries, — are  the  ascending  pharyngeal,  from  the  external  carotid, 
and  the  Vidian  (a.  canalis  pterygoidea)  from  the  internal  maxillary. 

Nerves, — are  pharyngeal  branches  from  the  glosso-pharyngeal,  pneumo- 
gastric  and  sympathetic,  through  the  pharyngeal  plexus,  also  the 
upper  posterior  nasal  branches  of  Meckel's  (spheno-palatine)  ganglion. 
The  otic  ganglion  lies  on  the  outer  side  of  the  cartilaginous  portion 
of  the  tube  (pars  cartilaginea  tubae  auditivae),  and  supplies  the 
tensor  palati  muscle  (m.  tensor  veli  palatini). 

THE  INTERNAL  EAR  OR  LABYRINTH  (AURIS  INTERNA) 

The  Internal  Ear  or  Labyrinth  is  the  essential  part  of  the  organ  of 
hearing.  It  lies  internal  to  the  tympanum,  within  the  petrous  portion  of 
the  temporal  bone,  and  consists  of  a  series  of  osseous  chambers,  the 
Osseous  Labyrinth,  containing  a  fluid,  the  perilymph,  in  which  lies  a  mem- 
branous reproduction  of  the  chambers,  the  Membranous  Labyrinth,  which 
also  contains  a  fluid,  the  endolymph.  Within  the  membranous  labyrinth 
are  distributed  the  terminal  filaments  of  the  auditory  nerve,  which  being 
suspended  between  two  fluids,  are  not  only  protected  from  injury,  but 
enabled  to  receive  the  most  delicate  vibrations  communicated  to  the  fluids 
surrounding  them.  The  Internal  Ear  comprises  the  following-named 
structures: — 

f  Vestibule  (4),  the  central  cavity. 

Osseous  Labyrinth {  Semicircular  Canals,  behind  the  vestibule. 

[  Cochlea  (8),  in  front  of  the  vestibule. 

Utricle,  a  membranous  sac,  in  the  recessus 
ellipticus  of  the  vestibule. 
I  Membranous     Semicircular    Canals    (ductus 

semicirculares),  in  the  osseous  canals. 
Membranous  Labyrinth.  \    _        . 

Saccule,  a  membranous  sac,  in  the  recessus 

sphaericus  of  the  vestibule. 
Membranous    Cochlea    (ductus  cochlearis),  a 
spiral  tube,  enclosed  in  the  osseous  cochlea. 

Auditory  Nerve  (n.  acusticus), — the  8th  cranial  nerve,  Portio  Mollis 

of  the  yth  pair. 
Organ  of  Corti  (organon  spirale), — the  terminal  auditory  apparatus,  in 

the  membranous  cochlea  (ductus  cochlearis). 


THE   EAR  305 

Internal  Auditory  Meatus  (meatus  acusticus  interims), — by  which  the 
auditory  nerve  enters  from  the  brain. 

The  Vestibule  (4)  is  the  central  common  cavity  of  communication  be- 
tween the  osseous  parts  of  the  internal  ear,  and  measures  in  vertical  diam- 
eter about  3-15  inch,  laterally  about  ^fo  inch.  It  is  situated  internal  to  the 
tympanum,  behind  the  cochlea  (8),  and  in 
front  of  the  semicircular  canals  (2),  communi- 
cating in  front  with  the  scala  vestibuli  of  the 
cochlea,  and  behind  by  five  openings  with  the 
semicircular  canals.  It  contains  a  fluid,  the 
perilymph,  also  the  utricle  and  saccule  of  the 
membranous  labyrinth,  and  presents  the  fal- 
lowing points: — 

Fenestra  Vestibuli  (fenestra  ovalis), — on  ils 
outer    wall,    closed   by   the   base   of    the 
stapes  and  its  annular  ligament. 
Recessus    Sphcericus    (fovea    hemisphaerica) 

(7), — a  small  circular  depression  on  the  inner  wall,  for  the  saccule, 
medially,  it  presents  a  small  area,  macula  cribrosa  media,  which  is 
perforated  by  12  to  15  minute  orifices  for  filaments  of  the  acoustic 
nerve. 
Crista  Vestibuli, — a  vertical  ridge  on  the  inner  wall  behind  the  recessus 

sphaericus.     It  bifurcates  below  to  enclose  the — 
Recessus  Cochlearis, — a  small  depression,  perforated  for  the  passage  of 

about  8  filaments  of  the  acoustic  nerve. 

Aquceductus  Vestibuli, — opens  behind  the  crista,  ending  on  the  posterior 
surface  of  the  petrous  portion  of  the  temporal  bone.  It  transmits  a 
small  vein,  and  contains  the  ductus  endo-lymphaticus,  a  tubular  pro- 
longation of  the  lining  membrane  of  the  vestibule,  which  ends  in  a 
cul-de-sac  between  the  layers  of  the  dura  mater  in  the  cranial  cavity. 
Recessus  Ellipticus  or  Fovea  Semi-elli plica  (6), — a  transverse  oval  de- 
pression on  the  roof  for  the  utricle;  behind  it  are  the  5  orifices  of 
the  semicircular  canals,  and  in  front  is  the  opening  into  the  scala 
vestibuli  of  the  cochlea. 

The  Semicircular  Canals  (canales  semicirculares  ossei)  are  three  C- 
shaped  bony  tubes,  each  about  >^o  inch  in  diameter,  situated  above  and 
behind  the  vestibule,  into  which  they  open  by  5  apertures.  Each  canal 
lies  at  a  right  angle  with  the  other  two.  The  external  (lateral)  canals  of 
both  ears  are  virtually  in  the  same  plane,  while  the  superior  canal  of  one 
ear  is  in  a  plane  parallel  to  that  of  the  posterior  canal  of  the  other  ear 


306  HUMAN    ANATOMY 

(Crum  Brown).  The  superior  and  posterior  canals  are  each  nearly  an 
inch  long,  and  are  placed  vertically;  they  join  together  behind  in  the  crus 
commune,  which  opens  into  the  vestibule.  The  external  canal  is  about  ^o 
inch  long,  placed  horizontally,  its  arch  being  directed  outward  and  back- 
ward. The  canals  contain  the  perilymph,  and  the  membranous  semicircu- 
lar canals.  The  — 

Ampulla,  —  is  a  flask-shaped  dilatation  of  each  canal  at  one  extremity, 
having  a  diameter  of  about  Ko  inch. 

The  Cochlea  is  a  spiral  canal  situated  in  the  eburnated  (ivory-like) 
portion  of  the  petrous  bone,  diametrically  opposite  to  the  internal  auditory 
canal  (meatus  acusticus  internus).  The  depth  at  which  it  lies  from  the 
cerebral  surface  of  the  bone  varies,  in  different  individuals,  from  ^4  to 
of  an  inch.  The  promontory  in 


the  tympanum  is  the  only  part  of  the 

cochlea  that  is  exposed,  elsewhere  it  is 

completely  imbedded  in  solid  bone.     It 

is  about  iM  inches  long,  tapering  from 

Ho    to    J^o   inch  in  diameter,   coiled 

around   a  central  conical  axis  for  2% 

turns.       By    removal    of    surrounding 

bone,   in  conformity  with  its  interior, 

the  cochlea  can  be  made  to  resemble  a  snail-shell  in  appearance  with 

its  apex  pointing  forward  and  outward.     Its  first  turn  is  separated  from 

the  carotid  canal  in  front  by  a  thin  wall.     Its  central  axis,  the  modiolus, 

is  of  conical  shape,  and  is  channeled  by  small  canals  for  the  passage  of 

arteries  and  nerves,  and  by  a  central  one,  the^canalis  centralis  modioli. 

Its  apex  is  the  last  coil  of  the  cochlea,  and  is  expanded  into  a  funnel- 

shaped  lamella,  iheJHfrmdibidum.     The  — 

Canalis  Spiralis  Modioli,  or  Spiral  Canal,  —  is  the  space  between  the 
modiolus  and  the  outer  wall  of  the  cochlea.  It  makes  2  ;34  turns;  from 
left  to  right  in  the  right  ear,  from  right  to  left  in  the  left  ear,  or  in  other 
words,  that  of  the  right  ear  corresponds  to  a  "  right  hand  "  screw;  and 
terminates  in  the  cupola,  a  cul-de-sac  at  the  apex  of  the  cochlea. 
It  presents  3  openings,  —  the  fenestra  cochlea  (fenestra  rotunda), 
communicating  with  the  tympanum;  the  opening  into  the  vestibule, 
and  the  orifice  of  the  aquaeductus  cochleae  (see  below). 
Lamina  .Spiralis  (6),  —  is  a  thin,  osseous  plate,  projecting  from  the 
modiolus  half  way  across  the  spiral  canal,  and  winding  around  the 
modiolus  terminates  near  the  apex  in  a  hook-like  process,  the  Jtajnidus^ 
Its  deficiency  in  the  last  half  turn  of  the  cochlea  forms  the  Helicotrema. 
a  space  in  which  the  two  scalae  unite.  It  consists  of  two  laminae, 


THE 'EAR  307 

between  which  pass  the  filaments  of  the  cochlear  nerve.  From  its 
free  edge  the  structures  composing  the  membranous  cochlea  pass  to 
their  attachment  on  the  opposite  wall  of  the  cavity.  It  partially 
divides  the  spiral  canal  into  2  passages,  the  scala  vestibuli  above  and 
the  scala  tympani  below. 

Aquceductus  Cochlea, — is  a  minute  funnel-shaped  canal  which  begins 
by  a  small  orifice  in  the  lower  wall  of  the  scala  tympani  near  the 
promontory,  and  runs  in  the  inner  wall  of  the  jugular  fossa,  ending  in 
the  small  deep  triangular  depression  on  the  posterior  border  of  the 
basilar  surface  of  the  petrous  portion  of  the  temporal  bone.  It 
transmits  a  vein  from  the  cochlea  to  the  jugular  vein,  or  to  the  inferior 
petrosal  sinus,  and  forms  a  communication  between  the  perilymph 
in  the  scala  tympani  and  the  subarachnoidean  space  of  the  brain. 

The  Membranous  Labyrinth  (labyrinthus  membranaceus)  is  situated 
within  the  osseous  labyrinth,  and  consists  of  two  membranous  sacs,  the 
Utricle  (utriculus)  (i)  and  Saccule  (sacculus)  (2),  together  with  the  Mem- 
branous    Semicircular     Canals     (ductus 
FlG-  IOI>  semicirculares)  (6),  and  the  Membranous 

Cochlea  (ductus  cochlearis)  (5).  The 
utricle  and  saccule  communicate  with 
each  other  indirectly  by  a  small  canal 
contained  in  the  aquaeductus  vestibuli. 
The  saccule  communicates  with  the 
membranous  cochlea  by  the  canalis 

reuniens  of  Hensen  (4),  and  the  mem- 
Acastof^fUabyrmthasseen         ^^    ^^^    canals    Qpen    into 

the    utricle;    so    that    the    membranous 

labyrinth  affords  an  uninterrupted  channel  for  the  endolymph  which  it 
contains.  The  walls  consist  of  3  layers, — an  outer  fibrous  coat,  a  middle 
one  resembling  the  hyaloid  membrane,  and  an  inner  layer,  formed  of 
polygonal,  nucleated  epithelial  cells.  In  the  walls  of  the  utricle  and 
saccule  are  contained  2  small  gelatinoid  bodies,  the  Macula  Acusticce 
which  contain  flask-shaped  Hair  Cells  and 

Otoliths  (otoconia), — minute  crystals  of  calcium  carbonate,  held  ta 

gether  in  a  mesh  of  delicate  fibrous  tissue  in  which  ramify  many 

minute  fibres  of  the  acoustic  nerve. 

The  Utricle  (utriculus)  (i)  is  a  flattened,  oblong  membranous  sac, 
fastened  to  the  inner  wall  of  the  vestibule  in  the  fovea  semi-elliptica 
(recessus  ellipticus).  It  is  filled  with  endolymph,  nearly  surrounded  by 
perilymph,  and  communicates  with  the  saccule  through  the  small  tube  in 


308  HUMAN   ANATOMY 

the  aquaeductus  vestibuli.     The  membranous  semicircular  canals  open 
into  its  cavity  behind  by  5  orifices.     The — 

Macula  Acustica  Utricularis, — is  a  thickened  spot  in  the  wall  where  it  is 
lodged  in  the  fovea  (recessus),  receiving  the  utricular  filaments  of  the 
acoustic  nerve. 

Ductus  Utriculosaccularis, — is  given  off  from  the  medial  wall;  it  is 
joined  by  a  similar  duct  coming  from  the  saccule;  together  they  form 
the  Ductus  Endolymphaticus  which  passes  through  the  aquaeductus 
vestibuli. 

The  Saccule  (sacculus)  (2)  is  the  smaller  of  the  two  membranous  sacs, 
about  Hs  inch  in  diameter,  attached  at  one  point  to  the  utricle,  and  also 
to  the  fovea  hemispherica  (recessus  sphaericus)  of  the  vestibule,  being  else- 
where surrounded  by  perilymph,  and  containing  endolymph.     It  com- 
municates with  the  utricle  through  the  ductus  endolymphaticus  in  the 
aquaeductus  vestibuli,  and  also  with  the  membranous  cochlea  by  the — 
Canalis  Reuniens  of  Hens  en  (4), — about  ^5  inch  long  and  K 20  inch  in 
diameter,- connects  the  cavity  of  the  saccule  and  the  vestibular  end 
of  the  membranous  cochlea  (ductus  cochlearis)  (3). 
Macida  Acustica  Saccularis, — is  a  circular  area,  ^2  inch  in  diameter, 
on  the  wall  of  the  saccule,  where  the  saccular  filaments  of  the  acoustic 
nerve  originate. 

FIG.  102. 


The  Membranous  Semicircular  Canals  (ductus  semicirculares)  have 
the  same  shape  as  the  osseous  ones  in  which  they  are  contained  but  are 
Yz  their  diameter.  They  are  fastened  thereto  by  the  convex  curves,  and 
are  elsewhere  surrounded  by  perilymph,  except  at  the  ampullary  enlarge- 


THE   EAR  309 

ments,  where  they  fill  the  osseous  canals  and  present  a  thickened  fiddle- 
shaped  elevation  projecting  into  the  cavity  and  called  the  septum  trans- 
versum,  in  which  the  nerves  end.  They  are  held  in  position  by  numerous 
fibrous  bands,  connecting  them  to  the  walls  of  the  osseous  canals.  They 
constitute  the  Organ  of  Orientation  and  Equilibration. 

The  Membranous  Cochlea,  also  called  the  Ductus  Cochlearis  or  Scala 
Media,  is  a  spiral  tube  enclosed  in  the  spiral  canal  of  the  osseous  cochlea 
(16),  lying  along  its  outer  wall,  to  which  it  is  attached,  being  also  attached 
to  the  lamina  spiralis  (10)  on  the  opposite  side  of  the  cavity.  It  is  formed 
by  the  membrana  or  lamina  basilaris  (8)  below,  the  vestibular  membrane 
of  Reissner  (18)  above,  and  the  periosteum  of  the  cochlear  wall  on  the  outer 
side,  its  cross-section  being  of  triangular  form.  It  is  filled  with  endolymph, 
and  contains  the  organ  of  Corti  (organon  spirale)  (n)  overhung  by  the 
membrana  tectoria  (7).  The — 

Limbus  Lamina  Spiralis  (10), — is  the  soft  structure  of  periosteum  on 
the  edge  of  the  lamina  spiralis,  and  lies  in  the  membranous  cochlea. 
It  has  two  lips, — an  upper,  the  labium  vestibulare,  and  a  lower,  the 
labium  tympanicum,  with  a  C-shaped  concavity,  the  sulcus  spiralis 
internus,  between  them. 

Vestibular  Membrane  of  Reissner  (18), — extends  from  the  edge  of  the 
lamina  spiralis  to  the  outer  cochlear  wall,  separating  the  membranous 
cochlea  from  the  scala  vestibuli  (2). 

Membrana  or  Lamina  Basilaris  (8), — is  the  tympanic- wall  of  the  mem- 
branous cochlea,  extending  from  the  labium  tympanicum  of  the 
lamina  spiralis  to  the  outer  cochlear  wall,  where  its  insertion  is 
called  the  ligamentum  spirale  (5),  or  muscle  of  Todd  and  Bowman. 
On  it  rests  the  Spiral  Organ  of  Corti  (n), — covered  by  the  mem- 
brana tectoria. 

Membrana  Tectoria  (7), — extends  parallel  to  the  membrana  or  lamina 
basilaris  from  the  'abium  vestibulare,  over  the  spiral  organ  of  Corti, 
to  be  attached  externally  to  the  outer  row  of  Deiters'  cells  (see  below). 
Vas  Spirale  (9), — a  vessel  in  the  vascular  connective  tissue  of  the  mem- 
brana or  lamina  basilaris,  below  the  spiral  organ  of  Corti. 
Zona  Arctuala, — is  the  inner  area,  and  the  zona  pectinata  is  the  outer 
area,  of  the  membrana  or  lamina  basilaris. 

The  Organ  of  Corti  (organon  spirale)  (n),or  Papilla  Spiralis,  is  situated 
on  the  inner  surface  of  the  membrana  or  lamina  basilaris  (8),  is  overlapped 
by  the  free  edge  of  the  membrana  tectoria  (7),  and  appears  as  a  papilla 
winding  spirally  throughout  the  length  of  the  membranous  cochlea. 
It  is  an  arrangement  of  cells,  some  of  which  are  rod-like  in  form,  and  others 


310  HUMAN   ANATOMY 

are  epithelial  hair-cells,  the  whole  being  supposed  to  be  the  essential  organ 

of  hearing.     The — 

Rods  of  Corti, — are  arranged  in  two  rows,  resting,  by  their  pedestals, 
on  the  lamina  basilaris,  and  uniting  with  each  other  by  their  heads, 
so  as  to  form  an  arched  tunnel,  the  tunnel  of  Corti,  between  them  and 
the  membrana  basilaris  all  along  the  length  of  the  cochlea.  Number 
of  rods  in  inner  row  about  6,000,  in  outer  row  4,000.  Average  di- 
ameter of  the  rods,  from  Msooo  to  Hsooo  inch. 
Head-plates, — are  attached  to  the  heads  of  the  inner  rods,  for  the  recep- 
tion of  the  rods  of  the  opposite  row. 


FIG.  103. 


Lamina  Reticularis  (i), — a  delicate  perforated  membrane  which  extends 
from  the  articulations  of  the  rods  outward  to  the  external  row  of 
the  outer  hair-cells. 

Auditory  Cells  (2), — are  epithelial  structures  covering  the  inner  surfaces 
of  the  walls  and  the  floor  of  the  membranous  cochlea.  Those  which 
cover  the  inner  rods  by  a  single  row  number  about  3,500,  are  nucleated, 
covered  with  tufts  of  cilia,  and  called  the  inner  hair-cells.  On  the 
outer  rods  are  3  or  4  rows  of  similar  cells,  numbering  about  12,000, 
and  named  the  outer  hair-cells.  Between  the  latter  are  rows  of  sup- 
porting cells,  called  the  cells  of  Deiters,  and  outside  them  are  5  or  6 
rows  of  columnar  cells,  the  cells  of  Hensen,  beyond  which  are  the  cells 
of  Claudius,  covering  the  outer  part  of  the  zona  pectinata  of  the 
membrana  or  lamina  basilaris. 

The  Auditory  Nerve  (n.  acusticus),  the  8th  or  Portio  Mollis  of  the  ;th 
pair,  arises  by  two  roots  from  the  same  groove  in  the  medulla  as  does  the 
facial  nerve  which  is  in  front  and  separated  from  it  by  the  pars  intermedia, 
or  glosso-palatine  nerve  (n.  intermedius),  the  medial  or  vestibular  root  from 
the  area  acustica  or  trigonum  acusticum  in  the  floor  of  the  4th  ventricle, 
the  lateral  or  cochlear  root  from  the  accessory  nucleus  and  the  tuberculum 
acusticum,  in  the  medulla,  close  to  the  restiform  body.  It  emerges  from 
the  medulla  at  the  lower  border  of  the  pons  Varolii,  in  company  with  the 
facial  nerve,  from  which  it  receives  one  or  two  filaments,  both  nerves 


THE    EAR  311 

passing  into  the  internal  auditory  meatus,  at  the  bottom  of  which  the 
auditory  divides  into  two  branches,  vestibular  and  cochlear.     The — 
Vestibular  Nerve, — has  a  ganglion,  the  vestibular  ganglion  of  Scarpa, 
on  it  in  the  internal  auditory  meatus;  it  then  divides  into  3  branches, 
which  pass  through  minute  orifices  in  the  bottom  of  the  meatus,  and 
entering  the  vestibule,  are  distributed  to  the  utricle  and  the  ampullae 
of  the  external  and  superior  semicircular  canals  respectively.     This 
nerve  has  nothing  to  do  with  hearing,  it  is  purely  a  nerve  of  orientation 
and  equilibration. 

Cochlear  Nerve, — is  the  true  nerve  of  hearing,  it  gives  off  branches  to  the 
saccule  and  the  ampulla  of  the  posterior  semicircular  canal,  and  then 
divides  at  the  base  of  the  modiolus  of  the  cochlea  into  numerous 
filaments  (14),  which  pass  through  the  little  foramena  in  the  tractus 
spiralis  foramenosus  at  the  bottom  of  the  internal  acoustic  meatus, 
then  between  the  lamellae  of  the  lamina  spiralis,  and  through  the 
central  canal  of  the  modiolus,  to  the  hair-cells  of  the  spiral  organ 
of  Corti  (Fig.  101).  On  it  in  the  spiral  canal  of  the  modiolus  is 
the— 

Ganglion  S pirate  (13), — consisting  of  bipolar  nerve-cells,  which  are  the 
true  cells  of  origin  of  this  nerve,  one  pole  being  prolonged  centrally 
to  the  brain,  and  the  other  peripherally  to  the  hair-cells  of  Corti's 
spiral  organ  (see  lateral  lemniscus,  page  199). 

The  Internal  Auditory  Meatus  (meatus  acusticus  internus)  is  a  large 
orifice  on  the  cerebellar  surface  of  the  petrous  portion  of  the  temporal 
bone,  leading  into  a  short  canal,  which  runs  outward  for  %  inch,  and  is 
closed  by  a  vertical  plate,  thefundus  or  lamina  cribrosa,  divided  by  a  crest, 
the  crista  falciformis  (crista  transversa),  into  4  depressions,  which  are 
perforated  by  foramina  for  the  passage  of  the  branches  of  the  auditory 
nerve  into  the  labyrinth.  The — 

Tractus  Spiralis  Foraminosus, — is  the  anterior  lower  depression;  has  a 
number  of  foramina  spirally  arranged  and  opening  into  the  central 
canal  of  the  cochlea,  transmitting  the  nerves  to  the  cochlea. 
Area    Cribrosa    Media    (area    vestibularis    inferior), — just    below    the 

posterior  part  of  the  crest,  transmits  the  nerves  to  the  saccule. 
Foramen  Singulare, — behind  the  preceding  area,  for  the  nerve  to   the 

posterior  semicircular  canal. 

Area  Cribrosa  Superior  (area  vestibularis  superior), — above  the  crest 
posteriorly,  for  the  filaments  to  the  utricle  and  the  superior  and 
external  semicircular  canals. 

Opening  of  the  Aquaductus  Fallopii  (area  n.  facialis)  above  and  in  front, 
for  the  passage  of  the  facial  nerve. 


HUMAN   ANATOMY 

Vessels  of  the  Internal  Ear.  The  Veins  accompany  the  arteries,  and 
uniting  at  the  base  of  the  modiolus  empty  into  the  superior  petrosal  sinus 
or  into  the  lateral  sinus.  The  Arteries  are  the — 

Internal  Auditory,  br.  of  the  basilar  (from  the  vertebral), — accompanies 
the  acoustic  nerve  into  the  internal  auditory  meatus,  where  it  divides 
into  vestibular  and  cochlear  branches. 

Stylo-mastoid,  br.  of  the  posterior  auricular  (from  the  external  carotid), 
— sends  some  small  branches  to  the  cochlea. 

ORGANS  OF  DIGESTION  (APPARATUS 
DIGESTORIUS) 

The  Alimentary  Canal  is  a  musculo-membranous  tube,  about  30  feet 
in  length,  extending  from  the  mouth  to  the  anus,  lined  throughout  with 
mucous  membrane,  furnished  with  several  accessory  organs,  and  perform- 
ing the  functions  of  ingestion,  mastication,  insalivation,  deglutition, 
digestion,  assimilation,  and  egestion.  Its  subdivisions  are  named  the — 
Mouth,  Pharynx,  (Esophagus,  Stomach,  Small  Intestine  (duodenum, 
jejunum  and  ileum)  and  Large  Intestine  (caecum,  colon  and  rectum). 
The  first  three  lie  above  the  diaphragm,  the  rest  below  it.  The  portion 
from  the  pharynx  down  is  the  "tubus  digestorius." 

Accessory  Organs  of  Digestion  are  the — Teeth,  Salivary  glands  (pa- 
rotid, sub-mandibular,  sub-lingual),  Liver,  and  Pancreas. 

THE  MOUTH  (CAVUM  ORIS) 

The  Mouth  is  an  oval-shaped  cavity,  placed  at  the  commencement  of 
the  alimentary  canal,  and  consists  of  the  vestibule,  and  the  cavity  proper. 
The  vestibule  (vestibulum  oris)  is  a  slit-like  aperture  between  the  lips  and 
cheeks  externally  and  the  gums  and  teeth  internally.  It  is  partially 
interrupted  in  front  in  the  mid-line  by  ihejrenula  which  attach  the  lips 
to  the  gums,  the  frenulum  of  the  upper  lip  being  the  more  developed  of  the 
two.  The  cavity  proper  (cavum  oris  proprium)  extends  from  the  alveolar 
arches  and  their  teeth  in  front  and  laterally  to  the  isthmus  of  the  fauces 
behind,  by  which  constricted  aperture  it  communicates  with  the  pharynx. 
Its  roof  is  formed  by  the  palate,  its  floor  by  the  tongue  and  its  mucous 
membrane  reflected  to  the  lower  gum.  The  lips  (labia  oris)  are  the  two 
fleshy  folds,  which  surround  the  orifice  (rima  oris)  of  the  mouth,  the  cheeks 
(buccae)  forming  its  sides  and  being  continuous  with  the  lips  in  front;  both 
are  formed  of  skin  externally,  and  mucous  membrane  internally;  between 
which  are  muscle,  fat,  areolar-  tissue,  vessels,  nerves  and  glands.  The 


THE    PALATE  313 

mouth  presents  for  examination  the  tongue  (see  page  272),  the  gums  and 
teeth  (described  separately),  the  palate,  fauces,  tonsils,  and  openings  of 
ducts  from  the  salivary  glands.  Special  anatomical  features  presented 
by  the  mouth  are  the — 

Hamular  Process  of  the  Medial  Pterygoid  Lamina  of  the  Sphenoid  Bone, — 

may  be  felt  behind  the  last  upper  molar  tooth;  also  the  internal  ptery- 

goid  plate  (medial  pterygoid  lamina),  and  part  of  the  pterygoid  fossa. 
Coronoid  Process, — of  the  lower  jaw,  at  its  anterior  border. 
Posterior  Palatine  Artery, — at  the  inner  side  of  the  last  upper  molar 

tooth,  and  in  front  of  the  hamular  process. 
Pterygo-mandibular  Ligament, — is  felt  as  a  fold  posteriorly  to  the  last 

lower  molar  tooth. 
Lingual  Branch  of  the  $th, — the  gustatory  nerve, — passes  over  the  inner 

side  of  the  ramus  of  the  lower  jaw,  close  to  the  last  lower  molar  tooth. 
Openings  of  Stenson's  Ducts,  from  the  parotid  glands, — in  the  vestibule, 

one  on  each  cheek,  opposite  the  2nd  upper  molar  tooth. 
Openings  of  Wharton's  Ducts,  from  the  submandibular  or  submaxillary 

glands, — in  the  cavity  proper,  one  on  each  side  of  the  f raenum  (frenu- 

lum  linguae)  of  the  tongue. 
Openings  of  the  Ducts  of  Rivinus,  from  the  sublingual  glands, — 8  to  20 

on  each  side,  open  into  the  cavity  proper,  on  either  side  of  the  fraenum 

(freiiulum  linguae)  of  tbe  tongue. 

THE  PALATE  (PALATUM)  AND  TONSILS  (TONSILL.E  "PALATINE) 

The  Palate  forms  the  roof  of  the  mouth,  and  consists  of  the  hard  palate 
(palatum  durum)  in  front,  and  the  soft  palate  (palatum  molle)  behind. 
The  Hard  Palate  (palatum  durum)  is  formed  by  the  palate  process  of  the 
maxilla  and  the  horizontal  plate  of  the  palate  bone,  is  covered  with 
mucous  membrane,  which  is  closely  adherent  to  the  periosteum,  and 
presents  along  the  median  line,  a  linear  ridge  orjaphe,  which  terminates 
anteriorly  in  a  papilla  corresponding  to  the  inferior  opening  of  the 
anterior  palatine  fossa.  The  Soft  Palate  (palatum  molle)  is  a  movable 
fold  suspended  from  the  posterior  border  of  the  hard  palate,  and 
forming  an  incomplete  septum  between  the  mouth  and  the  pharynx. 
It  consists  of  a  fold  of  mucous  membrane,  enclosing  muscular  fibres,  an 
aponeurosis,  adenoid  tissue,  vessels,  nerves  and  mucous  glands;  and  is 
formed  by  fibres  of  the  following — 

Muscles,  5  on  each  side,  the — levator  palati,  tensor  veli  palati,  palato- 
glossus  (m.  glosso-palatinus) ,  palato-phafyngeus  (m.  pharyngo- 
palatinus),  and  the  azygos  uvulae  (m.  uvulae); — the  latter  forming 
with  its  fellow  the —  " 


314  HUMAN   ANATOMY 

Uvula, — a  conical-shaped,  pendulous  process,  which  hangs  down  from 
the  middle  of  the  free  border  of  the  soft  palate. 

Glosso- palatine  Arch  or  Anterior  Pillar  of  the  Fauces, — arches  downward 
and  forward  to  the  base  of  the  tongue,  and  contains  the  glosso-palatine 
muscle. 

Pharyngo-palatine  Arch  or  Posterior. Pillar  of  the  Fauces, — arches  down- 
ward and  backward  to  the  sides  of  the  pharynx,  and  contains  the 
palato-pharyngei  (m.  pharyngo-palatinus)  muscle. 

Isthmus  Faucium, — the  space  bounded  by  the  glosso-palatine  arches  of 
both  sides,  the  free  border  of  the  palate,  and  the  base  of  the  tongue. 
It  communicates  with  the  mouth  anteriorly  and  with  the  pharynx 
posteriorly. 

The  Tonsils  (tonsillae  palatinae)  or  A  mygdalee,  are  two  prominent  bodies, 
situated  one  on  each  side,  in  the  sinus  tonsillaris  between  the  anterior  and 
posterior  pillars  (glosso-palatine  and  pharyngo-palatine  arches)  of  the 
fauces,  and  nearly  an  inch  in  front  of  the  internal  carotid  artery.  Their 
inner  surfaces  show  12  to  15  orifices,  leading  into  recesses,  from  which 
follicles  branch  out  into  the  substance  of  the  gland.  The  follicles  are 
numerous,  and  are  surrounded  by  a  layer  of  closed  capsules  of  adenoid 
tissue,  and  a  plexus  of  lymphatic  vessels  communicating  with  the  deep 
cervical  glands.  The — 
Fossa  Supra-tonsillaris, — is  a  recess  above  the  tonsil,  and  is  covered  by 

the  plica  semilunaris,  a  fold  of  mucous  membrane. 
Arteries,  as  usually  given,  are — the  dorsalis  linguae,  from  the  lingual;  the 
ascending  palatine  and  tonsillar,  from  the  facial  (a.  maxillaris 
externa);  the  ascending  pharyngeal,  from  the  external  carotid; 
the  descending  palatine;  from  the  internal  maxillary;  and  a  twig 
from  the  small  meningeal.  As  a  matter  of  fact,  in  95  per  cent,  of 
all  cases  none  of  these  arteries  that  surround  the  tonsillar  fossa 
(sinus  tonsillaris)  and  form  a  plexus  around  it,  actually  penetrate 
directly  through  the  wall  and  capsule  into  the  tonsil.  The  ascending 
palatine  branch  of  the  facial  (external  maxillary)  and  the^escendin^ 
palatine  branch  of  the  internal  maxillary  arteries  form  a  plexiform 
anastomosis  which  is  quite  outside  of  the  fossa  (sinus  tonsillaris) 
and  well  above  and  behind  it. 

The  True  Tonsillar  Artery  is  formed  by  this  anastomosis,  it  passes 

downwards    between    the  capsule  and  muscular  aponeurosis  for  a 

distance  of  about  %  inch  before  penetrating  the  capsule  to  reach 

the  tonsil  (J.  Leslie  Davis). 

Veins, — accompanying  the  true  tonsillar  artery  is  a  vein  which  runs 


THE    SALIVARY   GLANDS  315 

upwards  to  the  palatine  plexus,  a  smaller  vein  emerges  from  the  tonsil 
in  company  with  the  other  vein,  then  turns  downwards  and  runs  be- 
tween the  capsule  and  the  wall  of  the  fossa  (sinus  tonsillaris)  to  reach 
the  pharyngeal  plexus  (J.  Leslie  Davis). 

Nerves, — are  derived  from  the  spheno-palatine  ganglion,  and  from  the 
glosso-pharyngeal. 

THE  SALIVARY  GLANDS  (GLANDULE  SALIVALES) 

The  Salivary  Glands,  communicating  with  the  mouth,  are  the  Parotid, 
the  Stibmandibular,  and  the  Sublingual  glands.  They  are  compound,  race- 
mose glands,  consisting  of  numerous  lobes,  made  up  of  smaller  lobules 
connected  together  by  dense  areolar  tissue,  vessels  and  ducts.  Each  lobule 
consists  of  the  ramifications  of  a  duct,  the  branches  terminating  in  dilated 
ends  or  alveoli,  on  which  the  capillaries  are  distributed,  and  which  are 
enclosed  by  a  reticulated  basement  membrane.  The  alveoli  are  lined  by 
cells,  which  secrete  a  mucous  secretion  in  the  sublingual  gland,  or  a  serous 
fluid  in  the  parotid  gland;  the  submandibular  producing  both  kinds. 
Mucous  Glands  are  also  found  in  the  mouth,  in  the  tongue,  the  tonsil,  and 
the  soft  palate. 

The  Parotid  Gland  (glandula  parotis)  (i)  is  the  largest  of  the  three 
salivary  glands,  and  weighs  from  %  oz.  to  i  oz.  Superficially,  it  lies  upon 

the  side  of  the  face,  below  and  in 
front  of  the  external  ear,  and  passes 
over  the  masseter  muscle  anteri- 
orly. Deeply,  it  lies  on  the  tym- 
panic plate  of  the  temporal  bone 
behind  the  articulation  of  the 
lower  jaw.  The  parotid  is  sur- 
rounded by  a  capsule  which  blends 
deeply  with  the  back  of  the  stylo- 
mandibular  ligament.  The  super- 
ficial portion  of  this  capsule  is  the 
parotid  fascia  (fascia  parotideo- 
masseterica).  The  capsule  is  de- 
rived from  the  deep  cervical  fascia, 

it  is  strongly  attached  to  the  lower  border  of  the  zygoma,  the  acoustic 
meatus,  anterior  border  of  the  sterno-mastoid  muscle,  stylo-mandibular 
ligament,  and  the  bucco-pharyngeal  fascia.  It  is  tenaciously  adherent 
to  the  gland  itself.  Passing  through  it  are  the  following — 

Structures,— the  external  carotid  artery  and  its  terminal  branches,  the 
posterior  auricular,  temporal,  and  internal  maxillary;  the  vein  formed 


HUMAN   ANATOMY 

by  the  union  of  the  temporal  and  internal  maxillary  veins,  the  facial 
nerve  and  its  branches,  branches  of  the  great  auricular  nerve,  and  the 
auriculo-temporal  branch  of  the  mandibular  nerve.  The  internal 
carotid  artery  and  the  internal  jugular  vein  lie  close  to  its  deep 
surface. 

Stenson's  Duct  (ductus  parotideus)  (2), — is  the  duct  of  the  parotid 
gland,  and  is  about  2^  inches  long.  It  begins  by  numerous  branches 
from  the  anterior  part  of  the  gland,  crosses  the  masseter  muscle, 
pierces  the  buccinator,  and  opens  on  the  inner  surface  of  the  cheek 
by  a  small  orifice  opposite  the  2nd  molar  tooth  of  the  upper  jaw. 

Soda  Parotidis, — is  a  small,  detached  portion  of  the  gland,  which 
occasionally  exists  as  a  separate  lobe,  just  beneath  the  zygomatic 
arch.  Its  duct  empties  into  Stenson's  duct,  where  the  latter  crosses 
the  masseter  muscle. 

Arteries, — are  derived  from  the  external  carotid. 

Veins, — empty  into  tributaries  of  the  external  jugular. 

Lymphatics, — terminate  in  the  superficial  and  deep  cervical  glands. 

Nerves, — are  derived  from  the  carotid  plexus  of  the  sympathetic,  the 
facial,  auriculo-temporal  and  great  auricular  nerves. 

% 

The  Submandibular  Gland  (glandula  submaxillaris)  (3)  lies  below  the 
jaw,  in  the  anterior  part  of  the  submandibular  triangle,  and  upon  the 
mylo-hyoid,  hyo-glossus,  and  stylo-glossus  muscles,  the  facial  artery  (a. 
maxillaris  externa)  lying  embedded  in  a  groove  in  its  upper,  posterior 
border.  Its  duct — 

Wharton's  Duct  (ductus  submaxillaris)  (4), — is  about  2  inches  long,  and 
opens  on  the  summit  of  a  papilla  at  the  side  of  the  fraenum  of  the 
tongue. 
Arteries, — are  branches  of  the  facial  (external  maxillary)  and  the  lingual; 

the  veins  following  the  course  of  the  arteries. 

Nerves, — are  branches  of  the  submandibular  or  submaxillary  ganglion, 
and  are  derived  through  the  ganglion  from  the  chorda  tympani,  the 
lingual,  and  the  sympathetic. 

The  Sublingual  Gland  (glandula  sublingualis)  (5)  is  the  smallest  of  the 
salivary  glands,  and  is  situated  beneath  the  mucous  lining  of  the  floor  of 
the  mouth,  at  the  side  of  the  fraenum  (frenulum  linguae)  of  the  tongue,  and 
in  contact  with  the  inner  surface  of  the  lower  jaw.     Its  ducts,  the — 
Ducts  of  Rivinus  (ductus  sublinguales  minores), — from  8  to  20  in  num- 
ber; some  join  Wharton's  duct  (ductus  submaxillaris),  others  open  on 
the  side  of  the  frenulum  linguae. 


THE   TEETH 


317 


Duct  of  Bartholin, — is  a  tube  formed  by  one  or  more  of  the  preceding 

ducts;  it  opens  into  Wharton's  duct  (ductus  submaxillaris). 
Arteries, — are  derived  from  the  sublingual  and  submental. 
Nerves, — are  branches  from  the  lingual  nerve. 

THE  TEETH  (DENTES) 

The  Teeth  are  32  organs  of  digestion,  situated  16  in  each  jaw,  where 
they  are  implanted  within  the  alveoli,  and  are  partly  surrounded  by  the 
gums.  In  each  half  of  each  jaw  there  are — 

Deciduous  or  Temporary  Teeth  (dentes  dicidui)  (5) — 2  Incisors,  i 
Canine,  2  Milk-molars. 

Permanent  Teeth  (dentes  permanentes)  (8) — 2  Incisors,  i  Canine,  2 
Premolar,  3  Molars. 

The  Gums  (gingivae)  are  composed  of  dense  fibrous  tissue,  closely 
connected  to  the  periosteum  of  the  alveolar  processes,  and  surrounding  the 
necks  of  the  teeth.  They  are  covered  with  mucous  membrane,  presenting 
numerous  fine  papillae  around  the  dental  margin,  and  reflected  into  the 
alveoli,  where  it  is  continuous  with  the  periosteal  lining  membrane. 

Characteristics  of  the  Teeth.  Each  tooth  consists  of  a — crown  (corona 
dentis)  or  body,  projecting  above  the  gum;  root  or  fang  (radix  dentis), 


embedded  within  the  alveolus;  and  the  neck  (collum  dentis),  the  constricted 
portion  between  the  crown  and  the  fang.  The  roots  are  entirely  con- 
cealed within  their  alveoli,  and  are  covered  by  the  pericementum  (perios- 
teum alveolare),  a  reflection  of  the  periosteum  lining  the  alveoli,  which 
becomes  continuous  with  the  fibrous  structure  of  the  gums.  The  pulp- 
cavity  (cavum  dentis)  occupies  the  centre  of  the  tooth,  opening  (foramen 
apicis)  at  the  apex  of  the  fang  for  the  passage  of  vessels  and  nerves  to 
the  pulp  (pulpa  dentis) .  Each  class  of  teeth  presents  the  following  charac- 
teristics: 


HUMAN   ANATOMY 


FIG.  107. 


Incisors,  or  Cutters  (denies  incisivi)  (i), — Crown  chisel-shaped,  beveled 

posteriorly.     Fang  single,  long,  thickest  antero-posteriorly. 
Canines,  or  Tearers  (dentes    canini)    (2), — Crown  thick  and  conical. 
Fang  longest  and  thickest  of  all  the  teeth,  forming  a  projection  on  the 
alveolar  arch.     The  2  upper  canines  are  the  "eye-teeth." 
Premolars,  or  Bicuspids  (dentes  prasmolares)   (3), — Crown  has  2  cusps 
(tubercles).     Fang  single  but  grooved  deeply,   showing  a   marked 
tendency  to  bifurcate. 

Molars,  or  Grinders  (dentes  molares)  (4), — Crown  large,  low  and  cuboid 
in  shape,  has  4  cusps  on  upper  molars,  5  on  the  lower  ones.  Fangs 
multiple,  usually  3  on  the  first  two  upper 
molars,  2  on  the  first  two  lower  ones.  The 
third  molar  (dentes  serotini)  (5)  is  called 
the  "wisdom-tooth,"  from  its  late  eruption; 
its  fangs  are  usually  fused  together  into  a 
grooved  cone. 

Structure  of  the  Teeth.  A  tooth  consists  of  3 
structures, — the  dentine,  or  ivory  (substantia 
eburnea)  the  proper  dental  substance,  forming 
the  larger  portion;  the  enamel  or  adamant  (sub- 
stantia adamantina),  a  layer  covering  the  crown; 
and  the  cement  (substantia  ossea),  a  thin  layer 
on  the  surface  of  the  fang.  A  central  chamber, 
the  pulp-cavity  (cavum  dentis),  occupies  the  in- 
terior, and  contains  the  pulp  (pulpa  dentis),  a 
soft,  vascular,  and  sensitive  organ,  surrounded 
by  a  layer  of  cells  the  odonto-blasts  or  dentine- 
forming  cells.  The — 

Pulp-cavity  (cavum  dentis), — has  a  process  ex- 
tending down  each  root,  and  opening  at  the 
apex  by  a  minute  orifice  (foramen  apicis) 
which  transmits  vessels  and  nerves  to  the 
pulp. 

Pulp  (pulpa  dentis), — is  made  up  of  myxoma- 
tous  tissue,  and  contains  numerous  blood- 
vessels and  nerves,  but  no  lymphatics. 
Dentine,  or  Ivory  (substantia  eburnea)  (2), — consists  of  tubules  (can- 
aliculi  dentales)  surr<  unded  by  the  inter-tubular  tissue  or  matrix,  and 
opening  into  the  pulp  cavity  (cavum  dentis).  It  resembles  compact 
bone  in  appearance  and  in  composition,  consisting  of  28  parts  animal 
matter  and  72  earthy  matter. 


THE    TEETH  3 19 

Dentinal  Tubidi  (canaliculi  dentales), — in  the  dentine,  are  delicate, 
wavy  canals,  diameter  about  M  5  o  o  of  an  inch,  which  branch  outwardly 
and  anastomose  with  each  other,  forming  concentric  shadings  called 
Schreger's  lines.  They  contain  slender  prolongations  from  the  proc- 
esses of  the  cells  of  the  pulp-tissue. 

Enamel  (substantia  adamantina)  (3), — covers  the  crown;  consists  of 
very  dense  tissue,  containing  but  3^  per  cent,  of  animal  matter. 
Its  earthy  matter,  96 ^  per  cent.,  is  composed  chiefly  of  the  phos- 
phate and  carbonate  of  calcium.  It  is  covered  by  a  delicate  epithelial 
cuticle,  Nasmyth's  Membrane  (cuticula  dentis),  which  when  intact 
withstands  the  action  of  acids. 

Crusta  Petrosa  (substantia  ossea)  or  Cement  (i), — the  enamel  of  the 
fang;  is  a  thin  layer  of  true  bony  tissue,  containing  lacunae,  canaliculi, 
and  occasionally  Haversian  canals. 

Development  of  the  Teeth.  The  teeth  are  evolved  from  the  dermoid 
system,  not  from  the  skeleton.  They  are  developed  from  two  of  the  primi- 
tive layers  of  the  embryo, — the  epiblasl  producing  the  enamel  (adamant) 
and  the  mesoblast  giving  rise  to  the  dentine  (ivory)  pulp,  cement  (sub- 
stantia ossea),  and  pericementum  (periosteum  alveolare).  About  the 
7th  week  of  foetal  life,  two  parallel  ridges  arise  along  the  summit  of  each 
jaw,  and  a  corresponding  epithelial  lamina  sinks  into  the  mesoblastic  tissue 
beneath.  This  lamina  sends  off  10  cords,  one  for  each  tooth,  from  its  inner 
edge;  the  cords  expand  into  flask-like  forms,  and  gradually  assume 
the  forms  of  the  teeth,  constituting  their  enamel-organs.  They  meet  and 
enclose  papilla,  which  arise  from  the  mesoblastic  tissue,  forming  a  series 
of  sacs,  which  with  their  contents  are  the  dental  follicles,  having  fibrous 
septa  between  them.  In  each  follicle  the  vascular  papilla  has  on  its 
surface  a  layer  of  cells,  named  odontoblasts,  from  which  the  dentine  (ivory) 
is  developed  by  calcification,  the  remainder  of  the  papilla  forming  the  pulp 
of  the  tooth.  The  cement  (adamant)  is  produced  later  by  the  tissue  of 
the  dental  sac,  in  the  same  manner  as  bone  is  produced  by  periosteum. 
When  calcification  has  advanced  sufficiently,  the  pressure  of  the  teeth 
causes  the  absorption  of  the  gum  above  them,  the  teeth  erupt,  and  the 
fibrous  septa  ossify,  forming  the  alveoli,  which  embrace  the  necks  of  the 
teeth  in  a  firm  hold. 

The  10  permanent  teeth,  which  replace  the  temporary  ones  in  each  jaw, 
are  developed  from  special  germs  (enamel-organs)  which  arise  from  the 
lamina  behind  the  germs  for  the  temporary  teeth,  and  recede  into  the 
tissue,  to  enclose  mesoblastic  papillae,  and  go  through  the  same  process 
as  described  for  the  temporary  teeth.  These  germs  appear  about  the  i6th 


320  HUMAN    ANATOMY 

week.  The  6  superadded  permanent  teeth  arise  from  successive  back- 
ward extensions  of  the  lamina,  projected  from  the  back  of  that  tor  each 
preceding  tooth,  and  thus  forming  a  special  dental  germ  for  each  added 
tooth. 

Eruption  of  the  Teeth.  The  temporary  teeth  begin  to  appear  through 
the  gum  at  the  7th  month  after  birth,  the  lower  central  incisors  appearing 
first.  Their  eruption  ends  with  the  appearance  of  the  second  molars, 
about  the  age  of  two  years.  The  lower  teeth  slightly  antedate  the  upper. 
Their  formula  is  as  follows : — 

Mo.   Mo.    Ca.  In.   In.    In.    In.    Ca.  Mo.    Mo. 
f  Upper.  ,.i         i         i       i       i       i       i       i       i         i      =  10 1 

j \.    =  20 

[  Lower.  ..      i         i         1111111         i      =ioJ 
24       12       18       9       7       7       9     18     12       24  months. 

Of  the  permanent  teeth,  the  first  molars  appear  about  the  end  of  the  6th 
year,  followed  by  the  incisors  about  the  7th  or  8th  year,  the  bicuspids 
from  the  9th  to  the  loth  year,  the  canines  about  the  nth  or  i2th  year, 
the  second  molars  from  the  i2th  to  the  i3th  year,  and  the  third  molars 
from  the  i7th  to  the  2ist  year.  Those  of  the  lower  jaw  are  slightly  in 
advance  of  the  corresponding  upper  ones.  Their  formula  is  as  follows: — 

Wis.Mo.Mo.Pm.Pm.Ca.In.In.In.In.Ca.Pm.Pm.Mo.Mo.Wis. 
r  Upper,  i     i      i      i      i      i     iiiiii      i      i       i       1=16] 

f32 

I  Lower,  i     i      i      i      i      1111111      i      i       i       i  =  16  J 
19  12      6    10     9    ii     8     7    7    8  n     9    10     6     12     19  years. 

The  greatest  number  of  teeth  at  one  time  in  the  jaws  is  48, — including  all 
the  temporary  and  permanent  teeth  except  the  third  molars,  if  none  have 
been  lost.  This  occurs  between  the  5th  and  7th  years  of  age. 

THE  PHARYNX 

The  Pharynx  is  a  conical,  musculo-membranous  tube,  about  4^  inches 
long,  hung  base  up  from  the  basilar  process  of  the  occipital  bone,  and 
extending  to  the  lower  border  of  the  cricoid  cartilage  posteriorly,  or  the 
5th  cervical  vertebra,  where  it  becomes  continuous  with  the  oesophagus  (5). 
It  forms  that  part  of  the  alimentary  canal  which  lies  behind  the  mouth, 
being  incomplete  in  front  where  it  opens  into  that  cavity.  From  above 
downward  it  may  be  divided  into — the  naso-pharynx  (pars  nasalis), 
above  the  level  of  the  soft  palate;  the  oral  part  (pars  oralis),  between 


THE    PHARYNX 


321 


FIG.   108. 


the  levels  of  the  soft  palate  and  the  hyoid  bone;  and  the  laryngeal  part 
(pars  laryngea),  below  the  latter  level.     It  is  connected  with — 
Anteriorly, — the  internal  pterygoid  plate,  pterygo-mandibular  ligament, 
lower  jaw,  base  of  the  tongue,  cornua  of  the  hyoid  bone,  stylo-hyoid 
ligament,  thyroid  and  cricoid  cartilages  of  the  larynx. 

Posteriorly, — the  longus  colli  and  recti 
capitis  anticus  muscles,  and  by  loose 
areolar  tissue  to  the  first  5  cervical 
vertebrae. 

Laterally, — the  styloid  processes  and 
their  muscles,  and  is  in  contact  with 
the  common  and  internal  carotid  arte- 
ries, the  internal  jugular  vein,  the  Qth, 
loth,  1 2th  and  sympathetic  nerves, 
and  above  with  a  small  part  of  the 
internal  pterygoid  muscles. 
Above, — it  is  limited  by  the  body  of  the 
sphenoid  bone,  and  the  basilar  process 
of  the  occipital  bone. 
Openings  into  the  Pharynx, — are  7  in 
number;  the  2  posterior  nares,  (choanse), 
the  2  Eustachian  tubes  (tubae  audi- 
tivae),  the  mouth,  the  larynx  and  the 
oesophagus. 

The  Naso  -pharynx  (pars  nasalis  pharyn- 
gis)  is  that  portion  of  the  pharynx  lying  be- 
hind the  nose  and  above  the  level  of  the 
soft  palate.     Its  cavity,  unlike  the  rest  of 
the  pharynx,  always  remains  open.     The — 
Eustachian  Tube  (tuba  auditiva), — opens 
on  its  lateral  wall,  by  a  cleft-like  orifice 
(ostium   pharyngeum  tubae  auditivae), 
behind  the  inferior  meatus  of  the  nose, 
and  just  above  the  level  of  the  floor  of 
the  nasal  fossa. 

Pharyngeal  Tonsil, — a  mass  of  lymphoid 
tissue,  in  the  back  wall  of  the  pharynx, 
between  the  two  Eustachian  tubes  (tubae  auditivae). 
Bursa  Pharyngea, — an  irregular  depression  of  the  mucous  membrane 

in  the  jniddle  line  of  the  pharynx,  above  the  pharyngeal  tonsil. 
Cushion  (torus  tubarius)  or  Tubal  Prominence,— immediately  behind 


322  HUMAN    ANATOMY 

the  orifice  of  the  Eustachian  tube  (ostium  pharyngeum  tubae  auditivae), 

due  to  the  pressure  of  the  extremity  of  the  cartilage  of  the  tube. 

Fossa  ofRosenmiiller, — a  deep  recess,  behind  the  cushion  (torus  tubarius). 

Structure  of  the  Pharynx.     The  pharynx  is  composed  of  3  coats, — a 

mucous,  a  muscular  and  a  fibrous,  the  latter  lying  between  the  other  two, 

and  called   the  pharyngeal  aponeurosis   (fascia  pharyngo-basilaris)    (4). 

The  mucous  coat  is  covered  with  ciliated  columnar  epithelium  above  the 

level  of  the  floor  of  the  nares — below  that  level  with  squamous  epithelium; 

and  contains  racemose  mucous  glands,  especially  around  the  orifices  of  the 

Eustachian  tubes  (ostia  pharyngea  tubarum  auditivarum),  also  numerous 

crypts  or  recesses,  surrounded  by  lymphoid  tissue.     The — 

Pharyngeal  Aponeurosis  (fascia  pharyngo-basilaris)  (4), — is  thick 
above,  where  it  is  firmly  attached  to  the  basilar  process  of  the 
occipital  bone,  and  the  petrous  portion  of  the  temporal  bone.  Pos- 
teriorly it  presents  a  fibrous  band  or  raphe  in  the  median  line,  which 
gives  attachment  to  the  constrictor  muscles. 

Muscles, — are  the  inferior  (i),  middle  (2),  and  superior  (3)  constrictors 
of  the  pharynx,  the  stylo-pharyngeus  and  the  palato-pharyngeus  (m. 
pharyngo-palatinus),  which  have  been  described  on  page  83. 
Vessels  and  Nerves.     The  Arteries  of  the  pharynx  are  the   superior 
thyroid  and  ascending  pharyngeal,  also  the  pterygo-palatine  and  descend- 
ing palatine  branches  of  the  internal  maxillary;  all  from  the  external 
carotid.     The  nerves  are  branches  from  the — 

Pharyngeal  Plexus, — formed  by  the  pharyngeal  branches  of  the  vagus, 
glosso-pharyngeal,  external  br.  of  the  superior  laryngeal,  and  superior 
cervical  ganglion  of  the  sympathetic. 

?  *>  !?*y  THE  (ESOPHAGUS  OR  GULLET 

The  (Esophagus  is  a  musculo-membranous  tube,  about  9  inches  long, 
extending  from  the  5th  cervical  vertebra  and  the  upper  border  of  the 
cricoid  cartilage  of  the  larynx,  through  the  cesophageal  opening  (hiatus 
oesophageus)  in  the  diaphragm  to  the  cardiac  orifice  (cardia  ventriculi) 
of  the  stomach,  where  it  terminates  opposite  the  loth  thoracic  vertebra. 
In  the  neck  it  lies  between  the  trachea  and  the  vertebral  column,  resting 
in  part  on  the  longus  colli  muscle;  then  inclining  to  the  left  side  it  reaches 
the  posterior  mediastinum  behind  the  left  bronchus,  and  descends  in  that 
mediastinum,  at  first  in  front  of  the  thoracic  duct,  lower  down  to  its  left. 
The  (Esophagus  is  composed  of  3  coats,  as  follows: — 

Muscular  Coat  (tunica  muscularis), — has  longitudinal  fibres  externally, 
circular  fibres  internally,  which  are  continuous  with  the  fibres  of  the 


THE   ABDOMEN  323 

stomach  below,  and  with  those  of  the  inferior  constrictor  muscle 
above. 
Areolar  Coat  (tela  submucosa), — forms  a  loose  connection  between  the 

other  two  coats,  and  contains  the  cesophageal  vessels. 
Mucous   Coat    (tunica  mucosa), — in  thick  longitudinal  folds,  covered 
with  a  layer  of  stratified  pavement  epithelium.     The  oesophagus  is 
loosely  surrounded  by  an  additional  areolarcoat  (tunica  adventitia) 
which  loosely  connects  it  to  the  surrounding  structures. 
(Esophageal   Glands     (glandulae   cesophageas), — are  compound  racemose 
glands,  situated  in  the  submucous  tissue  throughout  the  tube,  but  most 
numerous  at  the  lower  end,  close  to  the  cardiac  orifice  (cardia  ventriculi) 
of  the  stomach. 

Arteries, — are  chiefly  branches  from  the  thoracic  aorta. 
Veins, — empty  into  the  vena  azygos  minor. 

Nerves, — are  branches  from  the  cesophageal  plexus  (plexus  gullae),  which  is 
formed  by  branches  from  the  vagus  and  the  cervical  sympathetic. 

THE  ABDOMEN 

The  Abdomen  is  a  large,  oval-shaped  cavity,  situated  between  the 
thorax  above  and  the  pelvis  below,  and  bounded — above,  by  the  diaphragm; 
below,  by  the  brim  of  the  pelvis;  posteriorly,  by  the  vertebral  column,  and 
the  fasciae  covering  the  psoaeand  quadrati  lumborum  muscles;  anteriorly 
and  laterally,  by  the  transversalis  fascia,  the  lower  ribs  and  the  venter  of  the 
ilium.  It  is  invested  internally  by  the  Peritoneum,  and  it  contains  the — 

Stomach.  Pancreas.  Abdominal  Aorta. 

Intestines.  Kidneys  and  Ureters.  Inferior  Vena  Cava. 

Liver.  Supra-renal  Capsules.  Receptaculum  Chyli. 

Gall-bladder.  Bladder  (when  distended).  Thoracic  Duct. 

Spleen.  Uterus  (during  pregnancy).  Solar  Plexus,  etc. 

Regions  of  the  Abdomen  (Regiones  Abdominis).  The  abdomen  is 
divided  into  9  regions  by  two  horizontal  planes, — one  at  the  level  of  the 
cartilages  of  the  loth  ribs  (sub-costal  plane),  another  at  the  level  of  the 
highest  points  of  the  crests  of  the  ilia,  and  2  vertical  or  lateral  planes 
from  the  cartilages  of  the  8th  ribs  to  the  centre  of  Poupart's  inguinal  liga- 
ment. The  9  regions  thus  formed  are  named  the — 

Right  Hypochondriac.  Epigastric.  Left  Hypochondriac. 

Right  Lumbar.  Umbilical.  Left  Lumbar. 

Right  Inguinal  or  Iliac.         Hypogastric.         Left  Inguinal  or  Iliac. 


324  HUMAN   ANATOMY 

Parts  contained  in  each  region  are  as  follows: — 

Right   Hypochondriac   Region, — contains   the   right  lobe   of   the  liver, 

hepatic  flexure  of  the  colon,  and  part  of  the  right  kidney. 
Epigastric  Region, — contains  the  right  two-thirds  of  the  stomach,  left 

lobe  and  part  of  the  right  lobe  of  the  liver,  gall-bladder,  duodenum, 

cceliac  axis,  solar  plexus,  pancreas,  parts  of  the  aorta,  inferior  vena 

cava,  vena  azygos,  and  thoracic 

duct,  the  supra-renal  capsules  and 

parts  of  the  kidneys. 
Left    Hypochondriac    Region, — con- 
tains the  fundus  of  the  stomach, 

spleen,  tail  of  the  pancreas,  splenic 

flexure  of  the  colon,  and  part  of 

the  left  kidney. 
Right  Lumbar  Region, — contains  the 

ascending    colon,    lower  half   of 

the  right  kidney,  and  part  of  the 

small  intestine. 
Umbilical, — contains  the  transverse 

colon,  transverse  duodenum,  part 

of  the  great  omentum  and  mesentery,  and  part  of  the  small  intestine. 
Left  Lumbar  Region, — contains  the  descending  colon,  lower  half  of  the 

left  kidney,  and  part  of  the  small  intestine. 

Right  Inguinal  or  Iliac  Region, — contains  the  right  ureter,  caecum,  ap- 
pendix vermiformis,  and  the  spermatic  vessels  of  that  side. 
Hypogastric  Region, — contains  convolutions  of  the  small  intestine,  the 

bladder  in  children  and  in  adults  when  distended,  and  the  uterus  dur- 
ing pregnancy. 
Left  Inguinal  or  Iliac  Region, — contains  the  left  ureter  and  spermatic 

vessels,  and  the  sigmoid  flexure  of  the  colon. 

Apertures  in  the  Walls  of  the  Abdomen  are  8  in  number,  for  the  trans- 
mission of  structures  to  or  from  it,  as  follows:  the — 
Opening  for  the  Vena  Cava  (foramen  venae  cavae), — in  the  diaphragm. 
Aortic  Opening  (hiatus  aorticus), — behind  the  diaphragm,  for  the  aorta, 

vena  azygos  minor,  thoracic  duct,  and  occasionally  the  left  sympathetic 

nerve  (see  page  94). 
(Esophageal  Opening   (hiatus  cesophageus), — in  the  diaphragm,  for  the 

cesophagus,  and  the  pneumogastric  nerves  (see  page  94). 
Umbilical  Opening, — in  the  anterior  wall,  transmitting  the  umbilical 

vessels  in  the  foetus,  but  obliterated  after  birth,  leaving  a  puckered 

depression,  named  the  umbilicus. 


THE  PERITONEUM 


325 


FIG.  no. 


Internal  Abdominal  Ring  (annulus  inguinalis  abdominis), — on  each  side, 
half  an  inch  above  Poupart's  ligament,  for  the  passage  of  the  sper- 
matic cord  in  the  male,  and  the  round  ligament  of  the  uterus  in  the 
female  (see  page  384). 

Femoral  or  Crural  Ring  (annulus  femoralis), — on  each  side,  just 
below  Poupart's  inguinal  ligament;  for  the  passage  of  the  femoral 
vessels.  This  opening  is  closed  by  the  crural  or  femoral  septum 
(see  page  388). 

THE  PERITONEUM 

The  Peritoneum  (peritonaeum)  is  a  large  serous  membrane,  which  forms 
in  the  male  a  closed  sac,  the  parietal  layer  (peritonaeum  parietale)  of  which 

lines  the  abdominal  walls,  its 
visceral  layer  (peritonaeum  vis- 
cerale)  being  reflected  more  or 
less  completely  over  all  the 
abdominal  and  pelvic  viscera. 
Its  free  surface  is  covered 
with  endothelium,  and  is 
smooth,  moist,  and  shining. 
Its  attached  surface  is  con- 
nected to  the  viscera  and  the 
11  parietes  of  the  abdomen  by 
the  sub-peritoneal  tela  or 
areolar  tissue  (tela  subserosa). 
In  the  female  it  is  not  a  closed 
sac,  the  free  extremities  of  the 
Fallopian  tubes  opening  di- 
rectly into  its  cavity.  The 
peritoneum  is  divided  by  a 
constricted  portion  of  its  tis- 
sue, at  the  foramen  of  Winslow 
(foramen  epiploicum)  (9), 
into  2  sacs,  the — 

Greater  Sac  (cavum  peri- 
tonaei), — extends  over  the 
anterior  two-thirds  of  the 
liver  (i),  behind  and 
above  the  stomach  (3);  below,  behind,  and  in  front  of  the  great 
omentum,  and  below  the  meso-colon  (12). 

Lesser  Sac  (bursa  omentalis)  or  Cavity  of  the  Great  Omentum, — extends 
behind  and  below  the  liver  and  stomach,  above  the  meso-coion, 


326  HUMAN   ANATOMY 

within  the  great  omentum,  and  behind  the  small  or  gastro-hepatic 
omentum  (ligamentum  hepatogastricum)  (2). 

The  Foramen  of  Winslow  (foramen  epiploicum)  (9)  is  an  opening  which 
connects  the  two  peritoneal  sacs  with  each  other.  It  is  formed  by  an  hour- 
glass constriction  of  the  peritoneum  caused  by  the  hepatic  artery  in  its 
curved  passage  forward  and  upward  from  the  coeliac  axis  to  the  transverse 
fissure  of  the  liver.  It  is  situated  behind  the  free  border  of  the  lesser 
or  gastro-hepatic  omentum  (ligamentum  hepatogastricum)  (2),  immedi- 
ately below  the  caudate  lobe  of  the  liver,  and  is  bounded  as  follows: — 

Anteriorly, — the  lesser  or  gastro-hepatic  omentum  (ligamentum  hepato- 
gastricum) (2),  containing  the  hepatic  artery,  portal  vein,  and  the 
ductus  communis  choledochus. 

Posteriorly, — the  inferior  vena  cava,  and  the  right  crus  of  the  diaphragm. 

Superiorly, — the  caudate  lobe  (processus  caudatus)  of  the  liver. 

Inferiorly, — the  duodenum,  and  the  hepatic  artery. 

The  Omenta  are  peritoneal  folds  which  pass  from  the  external  surface 
of  the  stomach  (3)  to  various  other  organs,  and  are  named  the  lesser  or 
gastro-hepatic,  the  great  or  gastro-colic,  and  the  gastro- splenic  omentum. 
The  "B.N.A."  disregards  this  distinction  and  classes  them  with  the 
true  ligaments. 

Lesser  or  Gastro-hepatic  Omenlum  (ligamentum  hepatogastricum)  (2), 
— consists  of  two  layers  of  peritoneum,  the  anterior  layer  belonging 
to  the  greater  sac  (cavum  peritonaei),  the  posterior  to  the  lesser 
sac  (bursa  omentalis).  It  ascends  from  the  lesser  curvature  of  the 
stomach  (3)  to  the  transverse  fissure  of  the  liver  (porta  hepatis) 
(i)  and  the  end  of  the  resophagus.  Its  right  margin  is  free  and 
rounded,  and  contains  between  its  layers  the — 

Hepatic  Artery  and  Portal  Vein.    Ductus  Communis  Choledochus. 
Hepatic  Plexus  of  Nerves.  Lymphatics. 

Great  or  Gastro-colic  Omentum  (omentum  majus), — consists  of  4  layers  of 
peritoneum,  the  most  anterior  and  superior  of  which  belong  to 
the  greater  sac  (cavum  peritonaei),  the  two  internal  to  the  lesser  sac 
(bursa  omentalis).  The  two  anterior  layers  descend  from  the 
stomach  and  spleen  over  the  small  intestines  (6),  and  then  ascend 
as  the  posterior  layers  to  enclose  the  transverse  colon  (4). 
Castro-splenic  Omentum  (ligamentum  gastrolienale), — connects  the 
stomach  with  the  spleen,  and  is  continuous  by  its  lower  border  with 
the  great  omentum.  It  contains  the  vasa  brevia  vessels  (aa.  gastricae 
breves). 


THE   PERITONEUM  327 

The  Mesenteries  (mesenteria)  are  folds  of  peritoneum  connecting  the 
various  parts  of  the  intestinal  canal  (except  the  duodenum)  to  the  posterior 
abdominal  wall.  Each  one  contains  the  vessels  of  the  part  which  it  sup- 
ports. They  are  the — 

Mesentery  proper  (mesenterium  commune)  (5), — connects  the  convolu- 
tions of  the  jejunum  (6)  and  ileum  to  the  posterior  abdominal  wall, 
and  contains  between  its  layers  the  mesenteric  vessels  and  nerves, 
the  lacteals,  and  the  mesenteric  glands. 

Transverse  Mesa-colon  (mesocolon  transversum)  (12) — connects  the 
transverse  colon  to  the  posterior  abdominal  wall,  and  is  formed  by 
the  two  posterior  layers  of  the  great  omentum  (omentum  ma  jus). 

Sigmoid  Meso-colon  (mesocolon  sigmoideum), — connects  the  sigmoid 
flexure  of  the  colon  to  the  left  iliac  fossa. 

Meso-rectum, — connects  the  upper  part  of  the  rectum  (14)  to  the  front 
of  the  sacrum,  and  contains  the  superior  hemorrhoidal  vessels. 

Ligaments  formed  by  the  Peritoneum  are  1 7  folds  of  peritoneum  which 
support  certain  organs,  viz. — 

Castro-splenic  (lig.  gastrolienale), — from  the  stomach  to  the  spleen. 

Hepatic  (ligamenta  hepatis), — the  longitudinal  (lig.  falciformehepatis), 
coronary  (lig.  coronarium  hepatis),  and  2  lateral  ligaments  of  the 
liver  (lig.  triangulare  dextrum  et  lig.  triangulare  sinistrum). 

Splenic  (lig.  lienorenale), — the  suspensory  ligament  of  the  spleen. 

Vesical, — the  false  ligaments  of  the  bladder,  5  in  number. 

Uterine, — 2  vesico-uterine,  2  recto-uterine,  and  2  lateral  or  broad  liga- 
ments of  the  uterus. 

Pouches  formed  by  the  Peritoneum,  as  it  passes  over  the  rectum  (14), 
vagina,  uterus  (7)  and  bladder  (8),  are  as  follows:  the — 

Recto-vesical  Pouch  (excavatio  rectovesicalis), — in  the  male,  between  the 

rectum  and  the  bladder. 
Recto-vaginal   or   Douglas'   Pouch    (excavatio    rectouterina    or   cavum 

Douglasi), — in  the  female,  between  the  rectum  and  the  posterior 

vaginal  wall. 
Utero-vesical  Pouch  (excavatio    vesicouterina), — in  the  female,  between 

the  anterior  wall  of  the  uterus  and  the  posterior  wall  of  the  bladder. 

Retro -peritoneal  Fossae  are  recesses  of  the  peritoneum,  forming  small 
pouches  in  certain  parts  of  the  abdominal  cavity;  any  one  of  which  may  be 
the  site  of  a  retro-peritoneal  hernia,  and  hernia  of  the  vermiform  appendix 
(processus  vermiformis)  frequently  occurs  into  one  of  the  pericaecal 
group.  The  lesser  sac  of  the  peritoneum  may  be  regarded  as  a  recess  of 


328  HUMAN   ANATOMY 

peritoneum  through  the  epiploic  foramen  of  Winslow.     The  others  are 
divided  into  3  groups,  as  follows : — 

Duodenal  Fosses, — 9  have  been  described,  of  which  3  are  fairly  constant, 
viz.;  the  inferior,  and  superior,. both  on  the  left  side  of  the  ascending 
portion  of  the  duodenum  (n);  and  the  duodeno-jejunal  (recessus 
duodenojejunalis),  bounded  above  by  the  pancreas  (10),  below  by 
the  left  renal  vein,  to  the  right  by  the  aorta  (13),  and  to  the  left  by  the 
left  kidney. 

Periccecal  Fossa, — are  the  ileo-colic  (recessus  ileocecalis  anterior),  in 
front  of  the  caecum;  the  ileo-cacal  (recessus  ileocecalis  posterior), 
behind  the  angle  of  junction  of  the  ileum  and  caecum;  and  the  sub- 
ccBcal  (recessus  ileocecalis  inferior),  immediately  behind  the  caecum. 
Intersigmoid  Fossa, — lies  behind  the  sigmoid  meso-colon,  and  in  front 
of  the  parietal  peritoneum,  on  the  external  iliac  vessels.  It  is  con- 
stant in  the  foetus  and  during  infancy,  but  disappears  in  a  certain 
percentage  of  cases  as  age  advances. 

^Appendices  Epiploica, — are  small  pouches  of  peritoneum  situated  along 
the  colon  and  upper  third  of  the  rectum,  and  filled  with  fat.     They 
are  chiefly  found  along  the  transverse  colon. 
Viscera  invested  by  Peritoneum  are  the  following-named: — 
Liver  (i)  (almost  wholly). '  Transverse  Colon  (4). 

Stomach  (3)  (almost  wholly).         Sigmoid  Flexure. 
Spleen.  Rectum  (upper  ^). 

Duodenum  (n)  (first  part).  Ovaries. 

Small  Intestine  (6).  Uterus  (7). 

Those  partially  invested  by  peritoneum  are  the — • 

Duodenun  (descending  and  Descending  Colon. 

transverse  portions).  Rectum  (14)  (middle  third). 

Ccecum.  Vagina  (upper  part). 

Ascending  Colon.  Bladder  (8)  (posterior  wall). 

Those  having  no  peritoneal  investment  are  the — - 
Pancreas     (10).        Kidneys.        Supra-renal     Capsules     (glandulae 
suprarenales)  (see  page  324). 

THE  STOMACH  (VENTRICULUS) 

The  Stomach,  the  principal  organ  of  digestion,  is  a  dilated  part  of  the 
alimentary  canal,  situated  between  the  termination  of  the  oesophagus  and 
the  beginning  of  the  small  intestine.  It  is  somewhat  pyriform  in  shape, 
of  musculo-membranous  structure,  about  12  inches  long  by  4  inches  in 
average  diameter,  held  in  position  by  the  lesser  omentum,  and  situated 
diagonally  across  the  upper  abdomen,  in  the  epigastric  and  left  hypochon- 


THE    STOMACH 


329 


driac  regions,  above  the  transverse  colon,  below  the  liver  and  diaphragm 
It  presents  for  examination  a — 
Fundus  or  Upper  End   (c), — connected  to  the  spleen  by  the  gastro- 

splenic  omentum  (see  under  PERITONEUM). 

Pyloric  or  Lower  End, — lies  in  contact  with  the  anterior  wall  of  the  ab- 
domen, the  under  surface  of  the  liver,  and  the  neck  of  the  gall-bladder, 

its  position  being  near  the 
end  of  the  cartilage  of  the 
8th  rib. 

Greater  Curvature  (curvatura 
ventriculi  major)  (d), — is 
convex  and  is  connected 
to  the  colon  by  the  great 
omentum. 

Lesser  Curvature  (curvatura 
ventriculi  minor)  (i), — is 
concave,  and  connected 
to  the  liver  by  the  lesser 
omentum,  and  to  the  dia- 
phragm by  the  gastro- 
phrenic  ligament. 

(Esophageal  Orifice  (cardia)  (b), — is  situated  between  the  fundus  and 
the  lesser  curvature.  It  is  funnel-shaped,  and  the  highest  part  of 
the  organ. 

Pyloric  Orifice  (pylorus)  (k), — opens  into  the  duodenum  (/),  and  is 
guarded  by  the  circular  muscular  fibres  of  the  pylorus,  which  are  ag- 
gregated into  a  circular  ring,  projecting  into  the  cavity,  and  with  its 
covering  fold  of  mucous  membrane,  forming  the  Pyloric  valve. 

Structure  of  the  Stomach.  Its  wall  consists  of  4  coats, — the  serous, 
muscular,  areolar,  and  mucous;  together  with  vessels  and  nerves.  The — 

Serous  Coat  (tunica  serosa), — is  derived  from  the  peritoneum,  and  covers 
the  whole  external  surface,  excepting  the  points  where  the  gastro- 
splenic,  great  and  lesser  omenta  are  attached,  and  where  the  stomach 
is  in  contact  with  the  diaphragm. 

Muscular  Coat  (tunica  muscularis)  (/), — consists  of  longitudinal  (stratum 
longitudinale)  external,  circular  (stratum  circulare)  middle,  and 
oblique  (fibrae  obliquae)  internal.  The  longitudinal  fibres  radiate 
from  the  cardiac  orifice,  are  continuous  with  the  longitudinal  fibres 
of  the  oesophagus  and  the  small  intestine,  and  are  the  most  superficial. 
The  circular  fibres  lie  deeper,  form  a  layer  over  the  whole  organ,  and 


330  HUMAN   ANATOMY 

are  aggregated  into  a  circular  ring  at  the  pyloric  end,  which,  with  its 
lining  mucous  fold  forms  the  pyloric  valve.  The  oblique  fibres  lie 
deepest,  and  are  arranged  in  two  sets  around  the  cardiac  end. 

Areolar  or  Sub-mucous  Coat  (tela  submucosa), — consists  of  loose  areolar 
tissue,  connecting  the  muscular  and  mucous  coats,  and  contains  the 
gastric  vessels. 

Mucous  Coat  (tunica  mucosa)  (g), — lined  with  columnar  non-ciliated 
epithelium,  covered  with  polygonal  alveoli,  H  50  of  an  incn  in  diameter, 
containing  the  orifices  of  the  gastric  glands.  When  the  stomach  is 
contracted  the  mucous  membrane  lies  in  longitudinal  folds  or  ruga 
(h),  one  of  which  aids  in  forming  the  valve  at  the  pyloric  orifice. 

Gastric  Glands  (glandular  gastricae)  are  of  3  kinds,  named  pyloric, 
cardiac  and  fundus  glands,  all  tubular  in  character,  and  formed  by  a  deli- 
cate basement  membrane,  lined  by  epithelium.  The — 

Pyloric  Glands, — are  most  numerous  at  the  pyloric  end;  each  consists  of 
2  or  3  short,  closed  tubes,  opening  into  a  common  duct,  the  orifice 
of  which  is  situated  at  the  bottom  of  an  alveolus.  They  are  lined  with 
columnar  epithelium  throughout. 

Cardiac  Glands, — situated  close  to  the  cesophageal  opening  (cardia)  of 
the  stomach,  are  tubules  lined  part  way  with  columnar  epithelium, 
and  filled  with  nucleated  cells  in  their  deepest  parts. 

Fundus  Glands, — are  most  numerous  at  the  fundus  and  resemble  the 
pyloric  glands.  L"(  cJc 

Vessels  and  Nerves.  The  Arteries  of  the  stomach  are — the  gastric 
(a.  gastrica  sinistra),  the  pyloric  (a.  gastrica  dextra)  and  right  gastro- 
epiploic  branches  of  the  hepatic,  the  left  gastro-epiploic  and  vasa  brevia 
from  the  splenic  (a.  lienalis).  The — 

Veins, — terminate  either  in  the  splenic  (v.  lienalis)  and  superior  mes- 
enteric  veins,  or  directly  in  the  portal  vein. 

Nerves, — are  terminal  branches  of  the  right  and  left  pneumogastrics 
(nn.  vagi),  and  branches  of  the  semilunar  ganglia  (ganglia  coeliaca) 
of  the  sympathetic,  forming  the  gastric  plexus  (see  page  241). 

THE  SMALL  INTESTINE 

The  Small  Intestine  (intestinum  tenue)  is  a  convoluted,  tubular, 
digestive  organ,  about  20  feet  in  length,  extending  from  the  pylorus  to 
the  ileo-caecal  valve,  where  it  terminates  in  the  large  intestine.  It  is 
connected  to  the  spinal  column  by  the  mesenteric  portion  of  the  perit- 
oneum, and  divided  into  3  parts,  the — 


THE   SMALL   INTESTINE 


331 


FIG.   112. 


Duodenum  (d), — about  10  inches  long,  the  first  part  (pars  superior) 
ascends  for  2%  inches  to  the  under  surface  of  the  liver  and  the  neck 
of  the  gall-bladder,  the  second  part  (pars  descendens)  descends  for 
3^  inches  in  front  of  the  right  kidney,  and  the  third  part  (pars  hori- 
zontalis  inferior)  passes  transversely  for  4  inches  to  the  left,  across 

the  spinal  column,  to  the  left  side 
of  the  second  lumbar  vertebra, 
where  the  superior  mesenteric 
artery  crosses  its  junction  with  the 
jejunum.  The  last  inch  of  the 
duodenum  is  described  as  the 
fourth  or  ascending  portion  (pars 
ascendens).  The  duodenum  has 
no  mesentery,  is  partially  covered 
with  peritoneum,  and  surrounds 
the  head  of  the  pancreas.  Into 
its  descending  portion  open  the 
ductus  communis  choledochus  and 
the  pancreatic  duct. 
Jejunum  (intestinum  jejunum), — 
about  two-fifths  of  the  rest  of  the 
small  intestine,  its  coils  lying 
around  the  umbilical  region.  It  is 
named  from  the  fact  that  it  was 
formerly  supposed  to  be  found 
empty  (jejunus}  after  death. 
Ileum  (intestinum  ileum)  (i), — com- 
prises the  remainder  of  the  small 
intestine;  is  named  from  its  twisted 
course,  lying  below  the  umbilicus, 
and  terminating  in  the  right  iliac 
fossa,  at  the  ileo-cacal  valve,  or  valve 
of  Bauhin. 

Meeker s  Diverticulum  (diverticulum  ilei), — is  a  blind  tube  occasionally 
found  connected  with  the  ileum,  about  3^  feet  above  its  termination; 
it  represents  the  remains  of  the  vitelline  duct  of  early  foetal  life. 

Structure  of  the  Small  Intestine,  is  arranged  in  4  coats,  like  that  of  the 
stomach,  a  serous,  muscular,  areolar,  and  mucous  coat.  The — 

Serous  Coat  (tunica  serosa), — is  derived  from  the  peritoneum,  which 
partially  invests  the  duodenum,  and  completely  invests  the  jejunum 


332  HUMAN   ANATOMY 

and  ileum,  except  for  a  small  space  along  their  mesenteric  border, 
where  the  vessels  and  nerves  pass  in. 

Muscular  Coat   (tunica  muscularis), — consists  of  external  longitudinal 

(stratum   longitudinale)  and   internal   circular    (stratum   circulare) 

fibres,  the  former  being  thinly  distributed  along  the  bowel,  the  latter 

forming  a  thick  layer,  but  not  making  complete  rings. 

Areolar  Coat  (tela  submucosa), — contains  the  vessels  of  the  intestine, 

and  connects  the  muscular  and  mucous  coats  together. 
Mucous  Membrane   (tunica  mucosa), — is  covered  with  columnar  non- 
ciliated  epithelium,  and  thrown  into  crescentic  transverse  folds,  the 
valvulce  conniventes  (plicae  circulares),  or  valves  of  Kirkring.     It  pre- 
sents also  numerous  vascular  projections  or  Villi  (villi  intestinales), 
simple  follicles,  and  three  kinds  of  glands  (all  described  below). 
Villi  (villi  intestinales)  (/)  are  minute,  vascular  processes,  which  project 
from  the  mucous  membrane  of  the  small  intestine  throughout  its  whole 
extent,  giving  to  its  surface  a  velvety  appear- 
ance.    They  are  most  numerous  in  the  duode- 
num  and  jejunum,  and    altogether    number 
about  4  millions  for  the  whole  length  of  the 
intestine.     Each  villus  consists   of   a  lacteal 
vessel,   a    plexus    of    capillary    blood-vessels, 
epithelium,    basement    membrane,   and  mus- 
cular tissue,  supported  and  held  together  by 
retiform  lymphoid  tissue.     The — 

Lacteal  Vessel, — is  situated  in  the  axis  of  the 
villus,  and  commences  by  dilated  extrem- 
ities near  its  summit. 
Blood-vessels, — form    a   plexus  between  the 

lacteal  and  the  basement  membrane,  enclosing  the  cells  of  the  villus 
in  their  interstices. 

Basement  Membrane, — surrounds  the  preceding,  and  is  made  up  of  a 
stratum  of  endothelial  cells,  upon  which  is  a  layer  of  columnar 
epithelium. 

Muscular  Tissue,— consists  of  longitudinal  fibres  prolonged  into  the  vil- 
lus from  the  muscular  tissue  of  the  mucosa. 

Simple  Follicles,  or  Crypts  of  Lieberkiihn  (glandulae  intestinales), — are 
minute,  tubular  depressions  of  the  mucous  membrane,  opening  be- 
tween the  villi,  their  orifices  appearing  as  minute  dots  on  the  surface 
of  the  mucous  membrane. 

Glands  of  the  Small  Intestine.  The  mucous  membrane  of  the  small 
intestine  contains  the  following  glands: — 


THE    LARGE    INTESTINES  333 

Duodenal  or  Brunner's  Glands  (glandulae  duodenales), — are  small,  com- 
pound glands,  found  only  in  the  duodenum  and  the  first  part  of  the 
jejunum,  being  most  numerous  near  the  pylorus.  In  structure  they 
are  identical  with  the  racemose  glands  of  the  mouth. 
Solitary  Glands  (noduli  lymphatici  solitarii), — are  lymphoid  organs, 
situated  throughout  the  intestine,  though  most  numerous  at  the  lower 
portion  of  the  ileum.  They  are  agminated  into  some  20  or  30  oval 
patches,  named — 

Peyer's  Patches  or  Glands  (noduli  lymphatici  aggregati), — on  the  sur- 
face opposite  to  the  mesenteric  attachments,  some  of  which  are  as 
much  as  4  inches  in  length.  They  are  most  numerous  and  largest  in 
the  ileum,  are  few  and  small  in  the  jejunum,  and  are  occasionally  seen 
in  the  duodenum. 

Vessels  and  Nerves.  The  Arteries  of  the  jejunum  and  ileum  are 
branches  of  the  superior  mesenteric  artery,  forming  an  intricate  plexus 
in  the  areolar  tissue,  which  gives  off  minute  vessels  to  the  glands  and  villi. 
The  duodenum  is  supplied  by  the  pyloric  (a.  gastrica  dextra)  and  pan- 
creatico-duodenal  branches  of  the  hepatic,  and  the  inferior  pancreatico- 
duodenal  from  the  superior  mesenteric.  The — 

Veins, — accompany  the  arteries  and  have  a  similar  course  and  arrange- 
ment. 
Lymphatics, — are  in  two  sets,  one  for  the  mucous  membrane  and  one 

for  the  muscular  coat. 

Nerves, — of  the  duodenum  are  derived  from  the  solar  plexus  (plexus 
cceliacus);  those  of  the  rest  of  the  intestine  from  the  sympathetic 
plexuses  around  the  superior  mesenteric  artery. 

THE  LARGE  INTESTINE  (INTESTINUM  CRASSUM) 

The  Large  Intestine  (intestinum  crassum)  extends  from  the  termination 
of  the  ileum  to  the  anus.  It  is  about  five  feet  long,  of  large  calibre,  and 
consists  of  the  same  coats  as  the  small  intestine,  the  mucous  being  smooth 
and  without  villi,  the  muscular  having  its  longitudinal  fibres  collected  into 
3  narrow  bands  (taeniae  coli)  producing  a  sacculation  (pouching)  of  its  wall. 
In  its  course  it  describes  an  arch  around  the  convolutions  of  the  small 
intestine,  and  is  divided  into  3  portions,  the  Caecum,  the  Colon,  and  the 
Rectum. 

The  Caecum  (intestinum  caecum)  is  a  large  blind  pouch,  about  2%  inches 
long  and  3  inches  broad,  situated  in  the  right  iliac  fossa,  immediately 
behind  the  abdominal  wall,  above  the  outer  half  of  Poupart's  ligament  (liga- 
mentum  inguinale),  and  below  the  ileo-caecal  valve,  which  opens  into  it. 


334  HUMAN   ANATOMY 

It  lies  free  in  the  abdominal  cavity,  its  closed  end  downward,  its  open  end 
upward  and  continuous  with  the  commencement  of  the  colon.     It  is  usu- 
ally enveloped  entirely  by  peritoneum,  and  presents  for  examination  the — • 
Vermiform  Appendix  (processus  vermiformis), — a  narrow,  worm-like, 
blind  tube,  averaging  3  inches  in  length,  directed  upward  behind  the 
caecum,  or  to  the  left  behind  the  ileum,  or  downward  and  inward  into 
the  true  pelvis.     Its  canal  communicates  with  the  caecum  by  an  orifice 
situated  below  and  behind  the  ileo-caecal  opening.     Sometimes  the 
orifice  of  the  vermiform  process  is  partially  guarded  by  a  crescentic 
fold  of  mucous  membrane  (valvula  processus  vermiformis)  which  is 
produced    on   its   upper   border.     Its   proximal    %    is   retained   in 
position  by  a  triangular  mesentery,  its  distal  ^<j   is  free  and  com- 
pletely covered  by  peritoneum. 

Heo-ccBcal  Valve,  or  Valve  of  Bauhin  (valvula  coli), — guards  the  en- 
trance of  the  small  intestine,  and  is  formed  by  two  crescentic  folds  of 
the  mucous  and  cellular  coats  and  circular  muscular  fibres  (labium 
superius  et  labium  inferius)  each  fold  being  covered  with  villi  on  the 
side  toward  the  ileum,  but  smooth  on  the  caecal  side. 

The  Colon  is  divided  into  4  parts, — the  ascending,  transverse,  and  de- 
scending colon  and  the  sigmoid  flexure.  The  Ascending  Colon  (colon 
ascendens)  (ac)  extends  from  the  caecum  upward  on  the  right  side  of  the 
abdominal  cavity,  to  the  under  surface  of  the  liver,  where  it  turns  to  the 
left,  forming  the  hepatic  flexure  (flexura  coli  dextra).  The  Transverse 
Colon  (colon  transversum)  (tc)  crosses  the  abdomen  from  right  to  left 
to  the  lower  end  of  the  spleen,  where  it  curves  downward,  forming  the 
splenic  flexure  (flexura  coli  sinistra).  The  Descending  Colon  (colon  de- 
scendens)  (dc]  passes  downward  along  the  outer  border  of  the  left  kidney, 
then  inward  along  the  outer  border  of  the  psoas  muscle  to  the  crest  of  the 
ilium,  where  it  terminates  in  the  Sigmoid  Flexure  (colon  sigmoideum)  or 
pelvic  colon.  The  latter  is  curved  like  an  /,  first  upward  and  forward, 
then  downward  into  a  loop,  which  terminates  in  the  rectum,  opposite  the 
left  sacro-iliac  symphysis.  The — • 

Peritoneum, — covers  the  transverse  colon  and  the  loop  of  the  sigmoid 
flexure  almost  completely,  forming  the  transverse  mesocolon  and  the 
sigmoid  mesocolon.  It  covers  the  ascending  and  descending  colon 
and  the  upper  part  of  the  sigmoid  flexure  on  their  anterior  surface  and 
sides. 

Mesocolon, — is  the  mesentery  of  the  colon,  connecting  the  transverse  por- 

'  tion  to  the  posterior  abdominal  wall  in  all  cases;  but  exists  for  the 

ascending  colon  in  26  per  cent.,  and  for  the  descending  colon  in  36 


THE    LARGE    INTESTINE  335 

per  cent,  of  the  cases.     The  sigmoid  mesocolon  connects  the  loop  of  the 
sigmoid  flexure  to  the  psoas  fascia. 

Phreno-colic  Ligament, — is  a  fold  of  peritoneum,  connecting  the  com- 
mencement of  the  descending  colon  with  the  diaphragm. 
Appendices  Epiploicce, — are  small  pouches  of  peritoneum  containing  fat, 
and  found  along  the  colon  and  part  of  the  rectum.     They  are  chiefly 
appended  to  the  transverse  colon. 

The  Rectum  (intestinum  rectum)  (r)  is  the  terminal  portion  of  the  large 
intestine,  and  extends  from  the  sigmoid  flexure  (colon  sigmoideum)  or 
pelvic  colon  to  the  anal  orifice  (a).  It  is  about  8  inches  long,  not  saccu- 
lated,  and,  though  not  straight,  is  straighter  than  the  rest  of  the  gut.  It 
curves  laterally  to  the  middle  of  the  sacrum,  and  backward  about  an  inch 
above  its  termination  at  the  anus,  where  it  forms  an  antero-posterior  slit, 
having  its  lateral  walls  in  apposition,  but  capable  of  considerable  disten- 
tion.  The  relations  of  the  rectum  are  as  follows: — 

First  Portion,  4  inches  long, — lies  on  the  left  pyriformis  muscle  and  the 
left  sacral  plexus  of  nerves;  to  its  left  are  the  left  ureter  and  the 
branches  of  the  left  internal  iliac  artery. 

Second  Portion,  3  inches  long, — in  the  male  subject  lies  just  behind  the 
trigonum  vesicae  and  the  vesiculae  seminales,  and  close  below  the  under 
surface  of  the  prostate  gland.  In  the  female  it  is  adherent  to  the 
central  portion  of  the  posterior  wall  of  the  vagina. 
Third  Portion  or  Anal  Canal,  i  to  i^  inch  long, — is  surrounded  by  its 
sphincters  and  the  levator  ani  muscle,  and  is  separated  by  the  peri- 
naeum  from  the  membranous  portion  and  bulb  of  the  urethra  in  the 
male,  from  the  vagina  in  the  female. 

Peritoneum, — invests  the  first  portion  almost  completely,  forming  the 
mesorectum,  which  connects  it  to  the  sacrum;  invests  the  second  por- 
tion in  front  and  laterally,  and  is  thence  reflected  to  the' bladder  in  the 
male  and  to  the  vagina  in  the  female.  The  third  portion  of  the  rectum 
has  no  peritoneal  investment. 
Sphincters  of  the  Rectum, — are  the  internal  sphincter  and  the  sphincter 

ani  (see  page  97). 

Valves  of  Houston  (plicae  transversales  recti), — are  3  transverse  folds  of 
the  mucous  lining,  of  semilunar  shape,  one  in  the  upper  part  of  the 
rectum  on  the  right  side,  another  about  the  middle  on  the  left  side 
and  the  third  in  front,  opposite  the  base  of  the  bladder. 
Glands  of  the  Large  Intestine.     The  simple  follicles  are  present  through- 
out its  entire  length,  and  are  more  numerous  than  in  the  small  intestine. 
The  solitary  glands  (noduli  lymphatici  solitarii)  are  most  abundant  in  the 


336  HUMAN    ANATOMY 

caecum  and  appendix,  but  are  scattered  irregularly  over  the  entire  canal. 
Brunner's  glands  and  villi  are  absent,  the  valvulae  conniventes  are  almost 
wanting. 

Vessels  and  Nerves.     The  Arteries  of  the  large  intestine  are  the  ileo- 
colic,  colica  dextra  and  colica  media  from  the  superior  mesenteric,  to  the 
caecum,  the  ascending  colon  and  the  transverse  colon;  the  colica  sinistra 
and  sigmoid  branches  of  the  inferior  mesenteric,  to  the  descending  colon 
and  the  sigmoid  flexure;  the  superior  hemorrhoidal  from  the  inferior  mesen- 
teric, the  middle  hemorrhoidal  from  the  internal  iliac,  and  the  inferior 
hemorrhoidal  from  the  pudic  (a.  pudenda  interna),  to  the  rectum.     The — 
Veins  of  the  Rectum, — commence  in  a  plexus  around  the  lower  end,  the 
hemorrhoidal  plexus,  which  gives  off  6  vessels  to  unite  into  a  trunk, 
the  superior  hemorrhoidal  vein.     The  plexus  communicates  also  with 
the  tributaries  of  the  middle  and  inferior  hemorrhoidal  veins,  estab- 
lishing a  communication  between  the  systemic  and  portal  circulations. 
Lymphatics, — open  into  the  mesenteric,  lumbar,  sacral  and  inguinal 

glands,  the  latter  receiving  the  vessels  from  around  the  anus. 
Nerves, — are  derived  from  the  sympathetic  plexuses  around  the  arteries 
which  are  distributed  to  the  large  intestine. 

THE  LIVER  (HEPAR) 

The  Liver  is  the  largest  gland  in  the  body,  weighing  from  3  to  4  pounds, 
and  measuring  all  the  way  from  3  to  9  inches  in  various  directions.     It 
is  situated  in  the  right  hypochondriac,  epigastric  and  part  of  the  left  hypo- 
chondriac regions;  has  5  fissures,  5  lobes,  5  ligaments,  and  5  sets  of  vessels, 
and  is  invested  by  peritoneum,  except  for  a  small  space  at  the  attachment 
of  the  coronary  ligament.     It  is  also  surrounded  by  a  fibrous  coat  which 
is  continuous  at  the  transverse  fissure  with  the  capsule  of  Glisson.     Its — 
Upper  Surface  (facies  superior), — is  convex,  in  relation  with  the  under 
surface  of  the  diaphragm  and  lower  6  or  7  ribs,  and  is  divided  into 
two  lobes  by  the  falciform  ligament. 

Under  Surface  (facies  inferior)  (Fig.  113), — is  concave,  covers  the  stom- 
ach, duodenum,  hepatic  flexure  of  colon  (flexura  colidextra),  right 
kidney  and  supra-renal  capsule,  and  is  divided  into  5  lobes  by  5 
fissures. 

Posterior  Surface  (facies  posterior), — direct  backwards  and  is  in  con- 
tact with  the  various  structures  forming  the  upper  part  of  the  poste- 
rior abdominal  wall.  It  is  flat  in  the  vertical  axis  but  is  deeply 
indented  by  the  vertebral  column,  and  deeply  grooved  by  the  vena 


THE    LIVER  337 

Anterior  Border  (margo  anterior), — is  sharp,  and  is  notched  in  two  places, 
one  at  the  fundus  of  the  gall-bladder  (vesica  fellea),  the  other  at  the 
round  and  falciform  ligaments.  It  corresponds  to  the  lower  border 
of  the  ribs  and  costal  cartilages,  descending  a  little  lower  during  deep 
inspiration  and  in  the  upright  posture. 

Posterior  Border  (margo  posterior), — rounded,  and  deeply  grooved 
(sometimes  channeled)  for  the  inferior  vena  cava  (13).  The  anterior 
and  posterior  borders,  together  form  the  inferior  border  (margo 
inferior). 

Fissures  of  the  Liver  are  5  in  number,  situated  on  the  inferior  and 
posterior  surfaces,  and  arranged  in  the  form  of  the  letter  H.  The  left 
limb  of  the  H  is  the  longitudinal  fissure  (fossa  longitudinalis  sinistra), 
divided  into  the  umbilical  fissure  (fossa  venae  umbilicalis)  anteriorly,  and 

FIG.  114. 


the  fissure  for  the  ductus  venosus  (fossa  ductus  venosi)  (8)  posteriorly;  the 
right  limb  is  formed  in  front  by  the  fissure  (fossa  vesicae  felleae)  for  the 
gall-bladder  (9),  behind  by  the  fissure  (fossa  venae  cavae)  (12)  for  the  vena 
cava  (13).  The  connecting  bar  of  the  H  is  the  transverse  fissure  (porta 
hepatis).  The— 

Longitudinal  Fissure  (fossa  longitudinalis  sinistra), — separates  the  left 
lobe  (lobus  hepatis  sinister)  from  the  lobus  Spigelii  (lobus  caudatus) 
and  the  lobus  quadratus.  Its  anterior  portion,  in  front  of  the  trans- 
verse fissure  (porta  hepatis),  is  the  umbilical  fissure  (fossa  venae 
umbilicalis),  containing  the  umbilical  vein  in  the  foetus,  and  its 


33^  HUMAN   ANATOMY 

remains,  the  round  ligament,  in  the  adult.  It  is  often  bridged  over 
by  a  process  of  liver  tissue,  the  pans  hepatis.  The  posterior  portion 
is  the  fissure  of  the  ductus  venosus  (fossa  ductus  venosi)  (8),  and  lodges 
the  slender  cord  which,  in  the  adult,  represents  that  foetal  vessel. 

Transverse  or  Portal  Fissure  (porta  hepatis), — is  about  2  inches  long, 
runs  from  the  longitudinal  fissure  to  the  right,  and  transmits  the  por- 
tal vein  (7),  hepatic  artery  (6)  and  nerves,  and  the  hepatic  duct  (n) 
and  lymphatics.  It  separates  the  quadrate  lobe  in  front  from  the 
caudate  (processus  caudatus)  and  Spigelian  (lobus  caudatus)  lobes 
behind. 

Fissure  for  the  Gall-bladder  (fossa  vesicae  felleae)  (9), — on  the  right  of  the 
longitudinal  fissure,  and  nearly  parallel  with  it,  extending  from  the 
anterior  border,  backward  to  near  the  right  end  of  the  transverse 
fissure. 

Fissure  for  the  Vena  Cava  (fossa  venae  cavae)  (12), — extends  obliquely 
upward  on  the  posterior  surface,  and  separates  the  Spigelian  lobe 
(lobus  caudatus)  from  the  right  lobe  (lobus  hepatis  dexter).  Occa- 
sionally this  fissure  is  a  complete  canal  in  the  substance  of  the  liver. 

Lobes  of  the  Liver  are  5  in  number,  but  three  are  mere  lobules  of  the 
right  lobe,  formed  by  the  smaller  fissures.     The — 

Right  Lobe  (lobus  hepatis  dexter)  (2), — is  much  the  largest,  and  presents 
the  three  small  fissures  and  four  shallow  depressions,  one  anteriorly  for 
the  colon,  another  posteriorly  for  the  kidney,  a  third  for  the 
duodenum,  and  a  fourth  for  the  supra-renal  capsule  (glandula 
suprarenalis) . 

Left  Lobe  (lobus  hepatis  sinister  (i), — is  divided  from  the  right  lobe  by 
the  longitudinal  fissure  (fossa  longitudinalis  sinistra),  and  rests  upon 
the  stomach. 

Quadrate  Lobe  (3), — in  front  of  the  transverse  fissure  (porta  hepatis) 
and  between  the  umbilical  fissure  (fossa  venae  umbilicalis)  and  that 
(fossa  vesicae  felleae)  for  the  gall-bladder. 

Lobus  Spigelii  (lobus  caudatus)  (5), — behind  the  transverse  fissure 
(porta  hepatis),  and  between  the  fissure  (fossa  ductus  venosi)  for  the 
ductus  venosus  and  that  (fossae  venae  cavae)  for  the  vena  cava. 

Caudate  Lobe  (processus  caudatus)  (4), — a  connecting  ridge  from  the 
lobus  Spigelii  (lobus  caudatus)  to  the  right  lobe;  it  separates  the 
fissure  for  the  vena  cava  (fossa  venae  cavae)  from  the  fissure  (fossa 
vesicas  felleae)  for  the  gall-bladder,  and  lies  directly  above  the  foramen 
of  Winslow  (foramen  epiploicum). 

Ligaments  of  the  Liver  are  5  in  number,  connecting  the  organ  to  the 


THE    LIVER  339 

under  surface  of  the  diaphragm  and  the  anterior  wall  of  the  abdomen. 

Four  are  folds  of  peritoneum;  one,  the  round  ligament,  is  the  obliterated 

umbilical  vein  of  the  foetus.     The — 

Suspensory  or  Falciform  Ligament  (lig.  falciforme  hepatis),  called  also  the 
Broad  and  the  Longitudinal  Ligament, — is  a  sickle-shaped  double  fold 
reflected  over  the  round  ligament  (lig.  tereshepatis)  andis  attached  to 
the  sheath  of  the  right  rectus  muscle  as  low  as  the  umbilicus,  and  to  the 
diaphragm. 

Coronary  Ligament  (ligamentum  coronarium  hepatis), — is  a  double  fold, 
containing  firm  areolar  tissue  in  its  interspace,  and  extending  from  the 
posterior  border  of  the  liver  to  the  diaphiagm. 

Lateral  Ligaments  2, — are  the  triangular  extremities  of  the  coronary 
ligament,  and  extend  from  the  liver  to  the  diaphragm.  They  are  also 
known  as  the  lig.  triangulare  dextrum  and  the  lig.  triangulare  sinis- 
trum. 

Round  Ligament  (lig.  teres  hepatis), — ascends  in  the  free  margin  of  the 
suspensory  ligament  (lig.  falciforme  hepatis)  from  the  umbilicus  to  the 
longitudinal  fissure  (fossa  longitudinalis  sinistra),  in  which  it  is  con- 
tinued to  the  vena  cava.  It  results  from  the  obliteration  of  the  fcetal 
umbilical  vein,  and  is  continued  on  the  posterior  surface  as  the  oblit- 
erated ductus  venosus  (8). 

+  tf  STRUCTURE  OF  THE  LIVER 

»  The  Liver  Substance  is  composed  of  numerous  lobules  (lobuli  hepatis) 
held  together  by  fine  areolar  tissue,  and  the  ramifications  of  the  hepatic 
artery  and  veins,  portal  vein,  hepatic  ducts,  lymphatics  and  nerves.  The 
whole  organ  is  invested  by  a  fibrous  coat,  and  by  a  peritoneal  coat  for  the 
greater  part  of  its  surface.  The — • 

Fibrous  Coat  (capsula  fibrosa  [Glissoni]), — is  formed  of  connective  tissue, 
and  is  inflected  at  the  transverse  fissure  (porta  hepatis)  along  the  ves- 
sels, forming  the  so-called  capsule  of  Glisson. 

Peritoneal  Coat   (tunica  serosa), — is  derived  from  the  gastro-hepatic 
(lesser)  omentum,  (ligamentum  hepatogastricum)  between  the  layers 
of  which  the  liver  is  received,  and  which  forms  4  of  its  5  ligaments. 
Parts  Uninvested  by  Peritoneum  are — on  the  anterior  and  superior  sur- 
faces, along  the  line  between  the  two  layers  which  form  the  suspensory 
ligament;  on  the  inferior  surface,  where  the  gall-bladder  is  attached,  and 
at  the  transverse  fissure  (porta  hepatis)  where  the  vessels  enter;  on  the  pos- 
terior surface  of  the  right  lobe,  a  strip  about  3  inches  broad,  where  the  liver 


340 


HUMAN   ANATOMY 


is  in  contact  with  the  diaphragm,  also  a  part  of  the  depression  for  the  supra- 
renal capsule  (glandula  suprarenalis). 

The  Lobules  (lobuli  hepatis)  (i)  are  small,  granular-looking  bodies,  of 
polygonal  shape,  and  about  3^o  inch  in  diameter,  clustered  around  the  sub- 
lobular  branches  of  the  hepatic  veins,  and  connected  together  by  con- 
nective tissue  (3),  blood-vessels,  ducts  (2),  and  lymphatics.  Each  lobule 
consists  of  a  mass  of  hepatic  cells,  surrounded  by  a  dense  capillary  plexus, 
and  contains  the  minute  beginnings  of  a  bile-duct,  the  so-called  biliary 
capillaries;  possessing  therefore  all  the  essential  constituents  of  a  secreting 
gland.  A  lobule  contains — 

FIG.  115. 


Hepatic  Cells, — each  about  Msoo  inch  in  diameter,  having  a  nucleus  and 
nucleolus,  yellow  coloring  matter,  glycogen  granules,  and  oil  globules. 
Lobular  Veins  (3), — forming  a  plexus  in  the  lobule.       \   , 
Intralobular  Vein  (4), — in  the  centre  of  each  lobule.      / 
Plexuses, — of  lymphatics,  nerves,  and  bile-ducts. 

The  Capsule  of  Glisson  (capsula  fibrosa)  is  the  fibrous  tissue  which  sur- 
rounds the  hepatic  vessels  in  the  transverse  fissure  (porta  hepatis),  and 
accompanies  them  in  their  course  throughout  the  substance  of  the  liver. 
It  is  continuous  with  the  fibrous  covering  of  the  organ.  The  hepatic  veins 
and  their  tributaries  are  not  invested  by  the  capsule. 

Nerves  of  the  Liver  are  branches  from  the  hepatic  plexus,  which  is  formed 
by  branches  derived  from  the.cceliac  plexus,  the  left  pneumogastric  (n. 
vagus)  and  the  right  phrenic  nerves. 


THE    LIVER 


341 


FIG.  116. 


VESSELS  OF  THE  LIVER 

Vessels  of  the  Liver  are  5  in  number,  the  hepatic  artery,  portal  vein, 
hepatic  veins,  hepatic  ducts  (ductus  hepaticus),  and  lymphatics,  all 
emerging  in  the  transverse  fissure  except  the  hepatic  veins,  which  enter  the 
fissure  (fossa)  for  the  vena  cava.  In  the  transverse  fissure  (porta  hepatis) 
all  the  vessels  are  enveloped  in  the  capsule  of  Glisson,  and  the  duct,  artery 
and  vein  are  situated  from  before  backward  in  the  order  named,  repre- 
sented by  the  letters  D AV.  Four  of  these  vessels  are  described  separately 
below,  the — • 

Lymphatics, — accompany  the 
blood-vessels  in  2  sets,  su- 
perficial and  deep;  the  latter 
beginning  in  lymphatic 
spaces  around  the  capillaries 
of  the  lobules,  and  accom- 
panying the  interlobular 
vessels.  They  enter  the 
lumbar  glands,  the  glands 
of  the  lesser  omentum,  those 
of  the  oesophagus  and  of  the 
lesser  curvature  of  the 
stomach. 

The  Hepatic  Artery  is  the  nu- 
trient vessel  of  the  liver;  it  arises 
from  the  cceliac  axis,  gives  off 
pyloric,  gastro-duodenal  and 
cystic  branches,  and  passes  up- 
ward in  front  of  the  foramen  of 
Winslow  to  the  transverse  fissure, 

where  it  divides  into  right  and  left  branches,  for  the  corresponding  lobes 
of  the  liver.     These  divide  and  subdivide,  ramifying  in  the  portal  canals 
throughout  the  organ,  and  giving  off  the  following  branches: — 
Vaginal  Branches, — to  the  capsule  of  Glisson. 
Capsular  Branches, — to  the  fibrous  covering  of  the  liver. 
Interlobular  (rami  arteriosi  interlobulares), — forming  an  arterial  plexus 

between  the  lobules. 
Lobular, — to  the  capillary  network  in  the  lobules. 

The  Portal  Vein  brings  blood  to  the  liver  from  the  stomach,  intestines, 
pancreas  and  spleen;  being  formed  by  the  union  of  the  superior  and  infe- 


342  HUMAN    ANATOMY 

rior  mesenteric,  splenic  and  gastric  veins,  all  the  main  veins  of  the  abdomen 
except  the  renal.  It  is  about  4  inches  long,  enters  the  transverse  fissure  of 
the  liver,  where  it  divides  into  the  right  and  left  portal  veins,  these  dividing 
into  branches,  which  receive  vaginal  and  capsular  veins,  and  ramify 
throughout  the  liver  as  portal  canals  (i),  in  company  with  the  branches  of 
the  hepatic  artery  and  duct;  finally  breaking  up  into  the — 

Inlerlobular  Plexus  (2), — between  the  lobules,  giving  off  the — 

Lobular  Veins  (3), — converge  to  the  centre  of  the  lobule,  and  end  in 
the— 

Intralobular  Vein  (4), — vertically  in  the  centre  of  each  lobule,  enters  the 
sublobular  of  the  hepatic  veins  below  the  lobule. 

The  Hepatic  Veins  convey  blood  away  from  the  liver,  and  are  con- 
tinuations of  the  intralobular  veins  of  the  portal  system,  beginning  as  the 
sublobular  veins  below  each  lobule,  uniting  finally  into  3  trunks  usually, 
which  enter  the  inferior  vena  cava  in  the  fissure  for  that  vessel.  On  sec- 
tion of  the  liver  the  hepatic  veins  gape  open,  being  adherent  to  the  liver 
substance;  the  portal  veins  are  closed,  being  surrounded  by  the  capsule  of 
Glisson. 

The  Hepatic  Ducts  carry  away  bile  from  the  liver.  They  begin  between 
the  cells  of  the  lobules,  in  minute  spaces,  the  bile-capillaries,  forming 
channels  which  radiate  to  the  circumference  of  the  lobule,  and  enter  an 
interlobular  plexus  between  the  lobules;  from  which  plexus  ducts  pass  into 
the  portal  canals,  are  enclosed  in  the  capsule  of  Glisson  with  the  portal 
vein  and  the  hepatic  artery,  and  join  with  other  ducts  to  finally  form  2 
main  trunks,  which  emerge  at  the  transverse  fissure,  and  by  their  union 
form  the  Hepatic  Duct  (see  below). 

EXCRETORY  APPARATUS  OF  THE  LIVER 

The  Excretory  Apparatus  of  the  liver  consists  of — the  Hepatic  Duct, 
formed  by  the  union  of  the  two  main  trunks  above-mentioned;  the  Gall- 
bladder, a  reservoir  for  the  bile;  the  Cystic  Duct,  the  duct  of  the  gall-bladder; 
and  the  Ductus  Communis  Choledochus  or  common  bile-duct,  formed  by  the 
junction  of  the  hepatic  and  cystic  ducts.  The — 

Hepatic  Duct, — about  i  %  inches  long;  is  formed  in  the  transverse  fissure 
by  the  union  of  the  two  main  biliary  ducts,  from  the  right  and  left 
lobes.  It  joins  the  cystic  duct  from  the  gall-bladder  to  form  the — • 
Ductus  Communis  Choledochus,  or  Common  Bile-duct, — is  a  fibro-mus- 
cular  tube,  covered  by  peritoneum  and  lined  with  mucous  membrane, 
about  3  inches  in  length,  formed  by  the  junction  of  the  Cystic  and 
Hepatic  ducts,  and  emptying  its  contents  (bile)  into  the  descending 


THE   PANCREAS  343 

part  of  the  duodenum  at  a  point  about  3  inches  from  the  pyloric 
orifice  of  the  stomach,  generally  in  common  with  the  duct  of  the 
pancreas. 

The  Gall-bladder  (vesica  fellea)  is  a  pear-shaped  bag,  3  to  4  inches  long, 
an  inch  in  greatest  diameter,  holding  from  8  to  12  fluid  drachms,  invested 
by  peritoneum  on  its  under  surface  and  f  undus,  formed  of  a  fibrormuscular 
coat  and  lined  by  a  mucous  one,  lying  in  a  fissure  on  the  under  surface  of 
the  liver,  close  to  its  anterior  border,  and  directed  obliquely  downward, 
forward,  and  to  the  right.  Its — 

F  undus  (f  undus  vesicae  felleae), — touches  the  abdominal  wall  immedi- 
ately below  the  gth  costal  cartilage,  and  is  completely  invested  by 
peritoneum. 
Neck  (collum  vesicae  felleae), — is  narrow  and  curves  like  the  letter  S;  it 

empties  into  the — 

Cystic  Duct  (ductus  cysticus), — about  i^  inches  long,  is  marked  inte- 
riorly by  spirally  arranged  crescentic  folds  of  its  mucous  lining,  and 
joins  with  the  hepatic  duct  at  an  acute  angle,  to  form  the  common 
bile-duct  (see  above). 

THE  PANCREAS 

The  Pancreas  is  a  compound  racemose  gland,  about  5  finches  long  and 
i^  inches  broad,  situated  transversely  across  the  posterior  wall  of  the  ab- 
domen behind  the  stomach  and  in  front  of  Jthe  first  lumbar  vertebra. 
Its  structure  resembles  that  of  the  salivary  glands,  being  composed  of  red- 
dish-yellow lobules,  vessels  and  ducts,  and  ending  in  closed  pouches  sur- 
rounded by  a  capillary  plexus. 
It  is  not  enclosed  in  a  capsule^ 
but  is  surrounded  by  areolar 
tissue,  which  extends  into  its 
interior,  and  connects  together 
23  *  the  various  lobules.  Its — 

Head     or     Right     Extremity 
(caput    pancreatis)    (i), — 

shaped  like  the  head  of  a  hammer,  lies  in  the  concave  curve  of  the 
duodenum,  in  front  of  the  common  bile-duct,  the  inferior  vena  cava, 
the  left  renal  vein,  the  right  crus  of  the  diaphragm,  and  the  aorta. 
Neck  (2), — about  an  inch  long,  lies  just  below  the  pylorus,  and  above 

the  transverse  portion  of  the  duodenum. 

Body  (corpus  pancreatis)  (3), — is  in  relation  anteriorly  with  the  ascend- 
ing layer  of  the  transverse  meso-colon,  the  posterior  wall  of  the  stom- 


344  HUMAN    ANATOMY 

ach  and  the  transverse  colon;  posteriorly  with  the  aorta,  splenic  vein 
(v.  lienalis),  origin  of  the  superior  mesenteric  artery,  crura  of  the 
diaphragm,  left  kidney  and  supra-renal  capsule,  and  the  left  quadratus 
lumborum  muscle. 

£gil  (cauda  pancreatis),  or  Left  Extremity  (4), — lies  above  the  left  kidney 
and  in  contact  with  the  lower  part  of  the  inner  surface  of  the  spleen. 

Pancreatic  Duct,  or  Duct  of  Wirsung  (5), — extends  the  whole  length  of 
the  gland,  commencing  by  the  junction  of  the  lobular  ducts  in  the 
tail,  it  receives  the  ducts  of  the  various  lobules,  and  opens  into  the 
descending  portion  of  the  duodenum,  about  3  or  4  inches  below  the 
pylorus,  usually  by  an  orifice  common  to  it  and  the  common  bile-duct, 
occasionally  by  a  separate  orifice.  Sometimes  the  pancreatic  duct  is 
branched,  in  which  case  the  upper  branch  is  known  as  the  duct  of 
Santorini  (ductus  pancreaticus  accessorius). 

'/,-  -JK4223& are  the~ 

Pancreatica    Magna    and    Pancreaticae    Parvae, — from    the    splenic 

(a.  lienalis). 

Pancreatico-duodenalis, — branch  of  the  hepatic  artery, 
inferior  Pancreatico-duodenalis, — branch  of  the  sup.  mesenteric. 
Veins, — open  into  the  splenic  and  superior  mesenteric  veins. 
Lymphatics,  terminate  in  the  lumbar  glands. 
Nerves, — are  filaments  from  the  splenic  plexus,  which  is  a  subdivision  of 

the  cceliac  plexus. 

The  Lesser  Pancreas  is  a  lobe  of  the  head  of  the  pancreas,  sometimes 
found  detached,  in  which  case  it  opens  by  a  duct  into  the  duodenum  about 
an  inch  above  the  orifice  of  the  pancreatic  duct. 

DUCTLESS  GLANDS 

The  Ductless  Glands  are  those  that  discharge  their  special  products 
directly  into  the  blood  or  lymphatic  circulation.  This  is  spoken  of  as 
internal  secretion,  which,  however,  is  not  peculiar  to  this  variety  of  gland, 
since  many  of  the  other  organs  such  as  the  liver,  pancreas,  stomach,  in- 
testine, kidney,  prostate,  testis,  uterus,  ovary,  corpus  luteum,  and  possibly 
still  other  organs,  form  internal  secretions  in  addition  to  their  obvious 
functions.  The  ductless  glands  are  classified  as  belonging  to  the  following 
systems: 

^.  Chromaphil  system. 

2.  Cortical  system. 

3.  Ductless  glands  of  ento-dermal  origin. 

4.  Ductless  glands  associated  with  the  vascular  system. 

THE   CHROMAPHIL  (chromafnn  or  phaerochrome)  SYSTEM  includes  those 
glands  which  elaborate  adrenin  (laevo-adrenalin  CgHisNOs  of  Aldrich) 


THE   DUCTLESS    GLANDS  345 

They  are  so  named  because  their  cell  cytoplasm  contains  granules  which 
are  stained  bright  yellow  to  dark  brown,  by  salts  of  chromium.  In 
this  system  are  included  the  following: — 

1.  Paraganglia  which  are  small  masses  of  chromaphil  tissue  associated 
with  the  ganglia  of  the  sympathetic  nervous  system.     They  may  be 
immediately  on  the  outside,  partially  within,  or  entirely  within  the 
capsules  of  the  sympathetic  ganglia. 

2.  Chromaphil  Bodies  of  the  Sympathetic  Plexuses.     These  are  asso- 
ciated with  the  abdominal  sympathetic  plexuses;  those  of  the  aortic 
plexus  are  called  the -aortic  bodies  which  are  situated  close  to  the  origin 
of  the  superior  mesenteric  artery. 

3.  Carotid  Glands  of  Bodies  (glomus  carotica)  are  found,  one  on  each 
side,  in  or  behind  the  bifurcation  of  the  common  carotid  artery. 

4.  The  Large  Cells  of  the  Anterior  (buccal  or  glandular)  lobe  of  the 
pituitary  body  (hypophysis)  (see  page  186). 

5.  Medullary  portions  of  the  supra-renal  glands  (see  page  363). 

THE  CORTICAL  SYSTEM  includes  several  masses  of  yellow  glandular  tissue 

which  is  rich  in  lipoids,  there  are  of  these, — • 

i'.  Cortex  of  the  Supra-renal  Glands  (see  page  363). 

2.  Accessory  Cortical  Bodies  which  are  several  small  masses  of  cortical 

tissue  found  in  relation  to  the  testis  and  ovary. 
DUCTLESS  GLANDS  OF  ENTODERMAL  ORIGIN  include  the  following, — • 

1 .  Small  Cells  of  the  anterior  (buccal  or  glandular)  lobe  of  the  Pituitary 
Body  (hypophysis)  (see  page  186). 

2.  Thyreoid  Gland  (glandula  thyreoidea)  is  an  incapsulated  gland  sur- 
rounding the  front  and  sides  of  the  upper  part  of  the  trachea,  and  the 
sides  of  the  lower  part  of  the  larynx,  under  cover  of  the  omo-hyoid, 
sterno-hyoid  and  sterno-thyreoid  muscles. 

The  Capsule  consists  of  a  superficial  layer  and  a  deep  layer.  The 
superficial  layer  of  the  capsule  is  derived  from  the  deep  cervical 
fascia.  It  is  strongly  attached  to  the  trachea  and  the  deep  cervical 
fascia.  It  is  attached  loosely  by  areolar  tissue  to  the  deep  layer  of 
the  capsule.  The  interval  between  the  two  layers  is  occupied  by 
numerous  large  blood-vessels,  the  veins  in  particular,  forming  a 
very  large  anastomotic  plexus. 

The  thyreoid  gland  itself  usually  consists  of  a  right  and  a  left  lobe 
the  lower  thirds  of  which  are  joined  together  across  the  mid-line 
by  the  isthmus.  Often  there  is  an  upward  production  of  the  upper 
border  of  the  isthmus  forming  a  pyramidal  lobe  which  is  usually 
to  the  left  of  the  mid-line.  Running  from  the  lower  border  of  the 
hyoid  bone  to  the  apex  of  the  pyramidal  lobe  is  the  hyo-thyreoid 


346  HUMAN    ANATOMY 

ligament  which  is  sometimes  muscular  (m.  levator  glandulae  thy- 
reoidea);  this,  together  with  the  attachments  of  the  superficial 
layer  of  the  capsule  to  the  trachea  and  deep  cervical  fascia,  holds 
the  gland  in  place. 

Deep  Layer  of  the  Capsule  (tunica  propria  glandulae  thyreoidea)  is 
intimately  attached  to  the  gland  itself  into  the  substance  of  which 
it  sends  many  supporting  trabeculce  and  septa  accompanied  by 
blood-vessels. 

Structure, — The  gland  is  made  up  of  many  irregular  masses  called 
lobules,  each  lobule  consists  of  several  closed  vesicles  which  do  not 
communicate,  each  vesicle  is  lined  with  a  single  layer  of  cuboidal 
or  columnar  cells,  and  filled  with  a  yellowish  viscous  substance 
called  colloid. 

Arteries  are, — the  right  and  left  superior  thyreoid  branches  of  the  ex- 
ternal carotid  arteries,  right  and  left  inferior  thyreoid  branches  of 
the  thyreoid  axes  of  the  subclavian  arteries,  and  when  present,  the 
thyreoidea  ima  branch  either  of  the  innominate  artery  or  arch  of 
the  aorta. 

Veins  are, — right  and  left  superior  thyr  eoid  veins  which  empty  into  the 
internal  jugular  veins,  right  and  left  middle  thyreoid  veins  which, 
when  present,  empty  into  the  internal  jugular  veins,  right  and  left 
inferior  thyreoid  veins  which  empty  into  the  innominate  veins, 
thyreoidea  ima  vein  which  when  present  empties  into  either  the  left 
innominate  vein  or  left  inferior  thyreoid  vein. 

Lymphatics  on  the  left  side  empty  into  the  upper  loop  of  the  thoracic 
duct  (ductus  thoracicus),  those  of  the  right  side  empty  into  the 
right  lymphatic  duct  (ductus  lymphaticus  dexter). 

The  nerve  supply  is  from  the  middle  and  inferior  cervical  ganglia  of 
the  sympathetic. 

3.  Parathyreoid  Glands, — are  small  flattened  ovoidal  masses  of  a 
yellow  or  reddish-brown  color,  they  are  slightly  lighter  in  color 
and  of  a  softer  consistency  than  the  thyreoid  gland  itself.  Each  is 
surrounded  by  its  own  individual  capsule  to  which  it  is  strongly 
adherent.  Each  gland  possesses  a  stalk  formed  by  the  blood- 
vessels entering  its  hilus.  The  capsule  sends  many  highly  vascu- 
lar supporting  trabeculae  and  septa  into  the  substance  of  the  gland 
which  is  composed  of  solid  masses  of  polyhedral  cells.  There  may 
be  a  considerable  variation  in  both  the  number  and  the  disposi- 
tion of  these  glands.  Normally  there  should  be  an  upper  and  a 
lower  pair. 

Superior  parathyreoids, — a  right  and  a  left,  are  usually  found,  nearer 


THE    DUCTLESS   GLANDS  347 

the  mid-line  than  the  lower  pair,  on  the  upper  ends  or  on  the  dorsal 
surface  of  the  upper  thirds  of  the  lateral  lobes  of  the  thyreoid  gland, 
inside  of  and  strongly  adherent  to  its  capsule;  or  they  may  be 
imbedded  in  the  areolar  tissue  between  the  two  layers  of  the 
capsule. 

Inferior  parathyreoids,  a  right  and  a  left,  usually  lie  on  the  dorsal  or 
lateral  surface  of  the  lower  thirds  of  the  lateral  lobes  of  the  thyreoid 
gland,  much  further  from  the  mid-line  than  the  upper  pair,  and 
more  often  outside  of  the  capsule.  Parathyreoids  that  have 
wandered  far  from  the  thyreoid  gland  can  hardly  be  identified 
except  under  the  microscope. 

4.  Thymus  Gland  (thymus), — consists  of  two  lateral  lobes  which 
are  firmly  united,  each  being  attached  by  a  ligament  to  the  lower 
end  of  the  lateral  lobe  of  the  thyreoid  gland  above  it.  The  thymus 
depends  from  these  suspensory  ligaments  in  the  lower  part  of  the 
front  of  the  neck  downwards  into  the  superior  and  anterior 
mediastina,  often  reaching  the  pericardium.  In  front,  it  is  in  rela- 
tion to  the  back  of  the  sternum,  the  sterno-thyreoid  and  sterno- 
mastoid  muscles.  Laterally  it  is  in  relation  to  the  pleurae.  Behind 
it  are  the  great  blood-vessels  which  deeply  groove  its  dorsal  surface 
although  actually  separated  from  it  by  the  deep  cervico-thoracic 
fascia.  The  thymus  is  subject  to  much  variation  both  in  size  and 
shape,  usually  it  is  relatively  largest  at  the  age  of  puberty,  becoming 
progressively  smaller  thereafter.  In  color  the  thymus  is  reddish 
gray,  tending  to  become  white  or  yellow  as  it  undergoes  involu- 
tion. It  is  invested  by  a  thin  fibrous  capsule  which  sends  nu- 
merous septa  into  the  gland  substance  dividing  it  up  into  lobules 
which  in  turn  are  divided  up  into  follicles.  Each  follicle  consists 
of  a  central  medulla  which  is  partially  surrounded  by  a  cortex 
which  resembles  lymphatic  gland  tissue. 

Arteries  are  numerous,  irregular  branches  of  the  internal  mammary 
and  inferior  thyreoid  arteries. 

Veins  are  numerous  and  irregular,  they  empty  into  the  inferior 
thyreoid,  internal  mammary,  and  left  innominate  veins. 

Nerves  are  small  branches  of  the  vagus  which  run  directly  into  the 
gland,  and  minute  branches  of  the  cervical  sympathetic  which  are 
carried  in  on  the  arteries. 

Lymphatics  arise  from  plexuses  around  the  follicles,  pass  through  the 
inter-lobular  septa  and  the  capsule  to  the  adjacent  lymph 
glands. 


HUMAN    ANATOMY 

DUCTLESS  GLANDS  ASSOCIATED  WITH  THE  VASCULAR 
SYSTEM 

i.  The  Spleen  (lien)  is  a  soft,  brittle,  highly  vascular  organ,  of  dark 
purplish  color,  in  size  about  5  by  3  by  i%  inches,  in  weight  about  7  ounces; 
situated  deeply  in  thejeft  hypochondrium,  between  the  fundus  of  the 
stomach  in  front  and  internally,  and  the  diaphragm  behind  and  externally, 
opposite  the  gth,  zoth  and  nth  ribs  of  thejeft  side.  It  is  connected  with 
the  stomach,  by  the  gastro-splenic  amentum  (ligamentum  gastrolienale); 
with  the  diaphragm,  by  the  suspensory  or  phreno-splenic  ligament;  and 
with  the  left  kidney,  by  the  lieno-renal  ligament,  all  of  which  are  folds  of 
peritoneum.  Its — 

Outer.  Surface  (facies  diaphragmatica), — is  convex,  smooth,  and  in  rela- 
tion  with   the  under  surface  of  the  diaphragm, 
which  separates  it  from  the  gth,  loth  and  nth 
ribs  of  the  left  side. 

Inner  Surface, — is  concave,  and  divisible  into  two 
portions,  one  that  is  in   contact,   anteriorly   (2) 
with  the  posterior  wall  of  the  cardiac  end  of  the 
stomach  and  the  tail  of  the  pancreas  (facies  gas- 
trica),  the  other  portion  being  in  contact  posteri- 
orly (i)  with  the  left  kidney  (facies  renalis). 
Hilum    (hilus   lienis), — a  vertical  fissure  about  the 
middle  of  the  inner  surface,  pierced  by  apertures 
for  the  vessels  and  nerves. 
Lower  End, — is  flat  and  triangular  (facies  colica  or  basalis),  and  rests 

upon  the  splenic  flexure  of  the  colon  and  the  phreno-colic  ligament. 
Anterior  Border  (margo  anterior)  is  between  the  gastric  surface  (facies 
gastrica)  and  the  diaphragmatic  surface  (facies  diaphragmatica),  it 
is  always  notched. 

Posterior  Border  (margo  posterior)  is  between  the  diaphragmatic  surface 
(facies  diaphragmatica)  and  renal  surface  (facies  renalis).  When  it 
is  present,  the  basal  surface  (facies  colica),  at  the  lower  end  of  the 
spleen,  is  separated  from  the  diaphragmatic  surface  (facies  diaphrag- 
matica) by  the  inferior  border  (margo  inferior),  from  the  gastric 
surface  (facies  gastrica)  by  the  anterior  intermediate  border  (margo 
intermedius  anterior,  and  from  the  renal  surface  (facies  renalis)  by 
the  posterior  intermediate  border  (margo  intermedius  posterior). 

Structure  of  the  Spleen.  A  fibre-elastic  capsule,  the  tunica  propria, 
forms  the  framework  of  the  spleen.  It  invests  the  organ  externally,  is 


STRUCTURES  OF  THE  SPLEEN  349 

reflected  inward  at  the  hilum  along  the  vessels,  and  gives  off  from  both 
parts  bands  or  trabeculce  lienis,  which  traverse  the  organ  in  all  directions 
and  unite  with  each  other,  to  form  a  sponge-like  structure,  having  numer- 
ous primary  spaces  or  areola,  in  which  the  pulp  is  contained.  The  splenic 
pulp  (pulpa  lienis)  looks  like  a  soft,  dark-red  mass,  resembling  grumous 
blood,  but  consists  of  branching  connective-tissue  corpuscles,  the  support- 
ing susientacular  or  reticular  cells,  which  form  a  delicate  reticulated 
tissue,  making  within  the  areolrc  a  number  of  secondary  spaces,  in  which  is 
blood  containing  a  large  proportion  of  whiteblood-corpuscles,  also  red 
blood-corpuscles  in  all  stages  of  disintegration.  These  secondary  spaces 
are  continuous  with  the  terminal  arterial  capillaries  and  the  primary 
venous  radicles,  both  of  which  open  into  them,  bringing  the  blood  supply 
into  relation  with  the  pulp  elements.  The  connective-tissue  coat  of  the 
arteries  is  converted  into  a  lymphoid  tissue  in  the  arterioles,  and  this  tissue 
presents  thickenings  of  spheroidal  shape,  the — • 

Malpighian  Bodies  (noduli  lymphatici  lienalis), — vary  from  Hoo  to 
^5  inch  in  diameter,  and  are  attached  to  the  arterioles  of  the  organ  in 
groups  of  6  or  8.  Their  reticulum  is  slender  and  open,  densely  filled 
with  lymphoid  cells  (leukocytes  and  spleen  phagocytes),  and  well 
supplied  with  capillaries. 

Peritoneal,  or  Serous  Coat  (tunica  serosa), — covers  the  whole  organ, 
except  at  the  hilum  and  the  attachments  of  the  suspensory  ligament 
and  the  gastro-splenic  omentum. 

Splenic  Artery  (a.  lienalis), — is  large  and  tortuous,  and  divides  at  the 
hilum  into  5  or  6  branches  (4),  each  supplying  a  segment  of  the  organ, 
and  terminating  in  capillaries  which  open  into  the  secondary  spaces. 
Veins, — arise  by  radicles  from  the  secondary  spaces,  and  anastomose 
freely,  joining  to  form  6  or  more  branches  (5)  which  emerge  from  the 
hilum  and  unite  into  the  splenic  vein  (v.  lienalis),  the  largest  of  the 
constituents  forming  the  portal  vein. 

Lymphatics, — are  superficial  and  deep;  the  two  sets  joining  in  the  inte- 
rior of  the  organ,  pass  through  the  lymphatic  glands  at  the  hilum,  and 
terminate  in  the  thoracic  duct. 

Nerves, — are  branches  of  the  splenic  plexus  (plexus  lienalis),  which  is 
formed  by  branches  from  the  cceliac  plexus,  the  left  semilunar  gan- 
glion (ganglion  coeliacum  sinistrum),  and  the  right  pneumogastric 
nerve  (n.  vagus  dexter). 

2.  Coccygeal  Gland  or  Body  (glomus  coccygeum)  is  a  minute,  highly 
vascular,  grayish-red,  spherical  body  capping  the  terminations  of  the  middle 
sacral  blood-vessels  which  form  its  stalk.  It  is  situated  in  the  mid-line 
just  beyond  the  tip  of  the  coccyx,  under  cover  of  the  coccygeal  attachment 


350  HUMAN   ANATOMY 

of  the  sphincter  ani  muscle  in  the  small  triangular  interval  between  the 
levator  ani  muscles.  It  is  invested  by  a  fibrous  capsule  which  sends  septa 
into  its  substance  dividing  it  up  into  follicles  or  nodules.  The  follicles 
are  masses  of  epithelial  cells  none  of  which  are  susceptible  of  staining  by 
chromium  salts.  Each  follicle  is  traversed  by  a  blood  space  or  sinus 
which  affords  free  intercommunication  between  the  arteries  and  veins  of 
the  gland. 

Nerve  supply  is  by  many  minute  fibres  from  the  sympathetic.  It  is 
not  uncommon  to  find  several  accessory  coccygeal  glands  which  in  all  es- 
sentials resemble  the  principal  gland. 

3.  Pineal  Gland  or  Body   (epiphysis  or  corpus  pineale)   while  classed 
as  a  ductless  gland,  is  probably  not  functional  in  man  (see  page  194). 

4.  Lymphoglandulse,  the  lymph  glands,  hcemal  lymph  glands,  and  hcemal 
glands  are  described  under  the  lymphatic  system  (see  page  172). 

ORGANS  OF  VOICE  AND  RESPIRATION 

THE  LARYNX 

.The  Larynx  is  a  musculo-membranous-cartilaginous  box,  the  essential 
organ  of  voice,  placed  at  the  upper  end  of  the  air-passage,  between  the 
trachea  and  the  base  of  the  tongue,  in  the  upper  and  fore  part  of  the  neck, 
where  it  forms  a  projection  in  the  middle  line.  Its  cartilages  are  9  in  num- 
ber, 3  single  and  3  in  pairs,  the — • 

Thyroid  Cartilage  (cartilage  thyreoidea).  ; 

Cricoid  Cartilage  (cartilago  cricoidea). 

Epiglottis  (cartilago  epiglottica). 

Arytenoid  Cartilages  2  (cartilagines  arytaenoideae). 

Cuneiform  Cartilages  2  (cartilagines  cuneiformes). 

Cornicula  Laryngis  2  (cartilagines  corniculatae). 

The  Thyroid  Cartilage  (cartilago  thyreoidea),  or  shield-like  cartilage, 
consists  of  two  Alee  or  wings  (&),  united  in  front  at  an  acute  angle,  the 
highest  portion  of  its  front  being  called  the  Pomum  Adami,  Adam's  apple 
(prominentia  laryngea).  Its — 

Outer  Surface, — affords  attachment  to  the  sterno- thyroid  (m.  sterno- 
thyreoideus)  thyro-hyoid  (m.  thyreo-hyoideus)  and  inferior  con- 
strictor muscles;  the  first  two  being  attached  along  its  oblique  ridge. 
Upper  Border, — is  curved  irregularly,  has  the  thyroid  notch  (incisura 
thyreoidea  superior)  (d)  in  front,  and  gives  attachment  to  the  thyro- 
hyoid  membrane. 


THE    LARYNX 


351 


Lower  Border, — gives  attachment  to  the  crico-thyroid  membrane  in  the 

median  line  and  on  each  side  to  the  crico-thyroid  muscle. 
Inner  Surface, — gives  attachment  to  the  true  and  false  vocal  cords,  the 
epiglottis,  thyro-arytenoid  and  thyro-epiglottidean  muscles,  and  the 
thyro-epiglottidean  ligament. 

Posterior  Border, — of  each  wing  ends  above  and  below  in  cornua  (horns), 
and  gives  attachment  to  the  stylo-  and  palato-pharyngeus  muscles. 

Superior  Cornu  (cornu  superius)  (a) — of  each  side 
affords  attachment  to  the  thyro-hyoid  ligament. 
Inferior  Cornu  (cornu  inferius)  (c] — of   each  side 
articulates  with  the  cricoid  cartilage  by  a  small 
oval  facet. 


PIG.  119. 


PIG.  1 20. 


The   Cricoid    Cartilage    (cartilago    cricoidea),   so 
called  from  its  ring-like  shape,  is  situated  below  the 
thyroid,  with  its  narrow  part  to  the  front.     It  has 
on  each  side  2  articular  facets,  one  on  the  upper  margin  posteriorly  for 
the  arytenoid  cartilage,  and  one  near  the  lower  margin  for  the  inferior 
cornu  of  the  thyroid  cartilage.     Its — 

Posterior  Portion  (lamina  cartilaginis  cricoideae), — is  deep  and   broad, 
gives  attachment  in  the  middle  line  to  the  longi- 
tudinal fibres  of  the  oesophagus,  and  on  each  side  to 
the  crico-arytenoideus  posticus  muscle  (m.  crico-ary- 
taenoideus  posterior). 

Anterior  Portion  (arcus  cartilaginis  cricoideae), — is 
narrow  and  convex,  and  affords  attachment  to  the 
crico-thyroid  muscles  and  part  of  the  inferior  con- 
strictor. 

Upper  Border, — affords  attachment  to  the  crico-thyroid  membrane  and 
the  crico-arytenoidei  laterales  muscles  (mm.  crico-arytaenoidei  later- 
ales),  and  articulates  with  the  arytenoid  cartilages. 
Lower  Border, — is  connected  to  the  upper  ring  of  the  trachea  by  fibrous 

membrane. 

The  Arytenoid  Cartilages  (cartilagines  arytaenoideae),  or  pitcher-like 

cartilages,  are  2  in  number,  pyramidal-shaped,  and  situated  on  the  upper 

margin  of  the  cricoid  cartilage  posteriorly,  closing  in  the  back  of  the 

larynx.    Each  cartilage  has  3  surfaces,  2  angles,  a  base  and  an  apex.   The — 

Anterior  Surface, — gives  attachment  to  the  plica  ventricular  is  or  false 

vocal  cord,  and   the  thyro-arytenoideus  muscle    (m.   thyreo-arytae- 

noideus). 

Anterior  Angle, — gives  attachment  to  the  plica  vacates  or  true  vocal 
cord  and  the  thyro-arytenoideus  muscle  (m.  thyreo-arytaenoideus). 


352 


HUMAN   ANATOMY 


PIG.  121. 


Posterior  Surface, — has  attached  to  it  the  arytaenoideus  (m.  arytae- 

noideus). 
Posterior  Angle, — gives  attachment  to  the  crico-arytenoideus  lateralis 

and  posticus  muscles  (mm.  crico-arytaenoidei  laterales  et  posterior). 
Internal  Surfaces  of  each — look  toward  each  other. 
Base, — has  a  facet  for  articulation  with  the  cricoid. 
Apex, — articulates  with  the  corniculum  laryngis. 
The  Cornicula  Laryngis  (cartilagines  corniculatae)  are  2 
small  cartilaginous  nodules  attached  to  the  apices  of  the 
arytenoid  cartilages,  and  are  also  called  the  Cartilages  of  Santorini.      To 
them    are    attached    the    aryteno-epiglottidean    folds    (plicae    arytaeno- 
epiglotticae). 

The  Cuneiform  Cartilages,  or  Cartilages  of  Wrisberg  (cartilagines  cunei- 
formes),  are  2  rods  of  yellow  elastic  cartilage  contained  in  the  free  borders 
of  the  aryteno-epiglottidean  folds  (plicaa  arytaeno-epiglotticee)  one  on 
each  side,  just  in  front  of  the  arytenoid  cartilages. 

The  Epiglottis  (cartilage  epiglottica)  is  a  cartilaginous  lid  for  the  larynx. 
It  is  leaf-shaped,  situated  behind  the  base  of  the  tongue,  and  attached  by 
its  apex  to  the  posterior  surface  of  the  thyroid  cartilage,  just  below  the 
median  notch.  Its — 

Base, — is  free,  and  curves  over  the  base  of 

the  tongue. 

Apex,  (petiolus  epiglottidis), — is  connected 
to  the  receding  angle  of  the  thyroid  car- 
tilage by  the  thyro-epiglottic  ligament. 
Anterior  Surface, — is  attached  to  the  hyoid 
bone  by  the  hyo-epiglottic  ligament,  and 
to   the   tongue   by  3  glosso-epiglottidean 
folds  (plicae  glosso-epiglotticae). 
Posterior  Surface, — covers  the  superior  aper- 
ture   of    the    larynx   when    food   passes 
through  the  pharynx. 

Lateral  Margins, — are  connected  to  the  ary- 
tenoid cartilages  by  the  aryteno-epiglotti- 
dean folds  (plicae  arytaano-epiglotticse). 
Ligaments  of  the  Larynx  are   20  in  num- 
ber,— 8  Extrinsic  Ligaments,  connecting  the  larynx  to  the  hyoid  bone 
(i),  the  tongue,  and  the  trachea  (15);  and  12  Intrinsic  Ligaments,  bind- 
ing its  several  cartilages  together.     The  Extrinsic  Ligaments  8  are  the — 
Hyo-epiglottic   Ligament, — connecting   the   hyoid   bone    (i)    with    the 
epiglottis  (2), 


FIG.  122. 


THE    LARYNX  353 

Glosso-epiglottic  Folds  three  (plicae  glosso-epiglotticae), — from  the  tongue 

to  the  epiglottis. 
Thyro-hyoid  Membrane  (membranahyo-thyreoidea)  (3), — connecting  the 

thyroid  cartilage  (n)  with  the  hyoid  bone  (i),  and  bounded  laterally 

by  the  two — 
Lateral    Thyro-hyoid   Ligaments    (ligamenta   hyo-thyreoidea  laterales) 

(6) — each  containing  a  nodule  of  cartilage,  the  cartilago  triticea. 
Crico-tracheal  Ligament, — from  the  cricoid  cartilage  (18)  to  the  trachea. 
Intrinsic  Ligaments  12,  are  the — 

Thyro-epiglottic  Ligament  (ligamentum  thyreo-epiglotticum), — connect- 
ing the  thyroid  cartilage  (u)  with  the  epiglottis  (2). 
Crico-thyroid  Membrane  (conus  elasticus)  (13), — connecting  the  cricoid 

(18)  and  thyroid  (n)  cartilages. 

Crico-thyroid  Capsular  Ligaments  2, — enclosing  those  articulations. 
Crico-arytenoid  Ligaments  (ligamenta  cricoarytaenoidea)  2, — connect  the 

cricoid  and  arytenoid  cartilages  together. 

Crico-arytenoid  Capsular  Ligaments  2, — enclosing  those  articulations. 
Superior  Thyro-arytenoid  or  Thyreo-arytenoid  Ligaments  2, — in  the  false 

vocal  cords  (plicae  ventriculares)  (5). 
Inferior  Thyro-arytenoid  or  Thyreo-arytanoid  Ligaments  2, — in  the  true 

vocal  cords  (plicae  vocales)  (9). 

Interior  of  the  Larynx  presents  a  cavity  which  is  divided  into  two  parts 
by  the  inward  projection  of  the  true  vocal  cords.  The  superior  part, 
sometimes  called  the  vestibule,  is  broad  and  triangular  in  shape;  the  inferior 
part  of  the  cavity  is  at  first  elliptical  and  lower  down  is  circular,  becoming 
continuous  with  the  tube  of  the  trachea.  The — 

Glottis  or  Rima  Glottidis, — is  a  narrow  chink  or  interval  between  the 
inferior  vocal  cords,  formed  by  the  projection  into  the  cavity  of  the 
larynx  of  these  cords  and  the  thyro-arytenoidei  muscles.  Its  greatest 
length  is  less  than  an  inch,  its  greatest  breadth  about  half  an  inch.  Its 
form  is  a  narrow  fissure  of  varying  width. 

Superior  or  False  Vocal  Cords  (plicae  ventriculares)  (5), — contain  the 
superior  thyro-arytenoid  ligaments,  extend  from  the  angle  of  the 
thyroid  cartilage  around  to  the  anterior  surfaces  of  the  arytenoids,  and 
consist  of  two  folds  of  mucous  membrane,  each  having  a  free  cres- 
centic  margin. 

Inferior  or  True  Vocal  Cords  (plicae  vocales)  (9), — contain  the  inferior 
thyro-arytenoid  ligaments,  extend  from  the  angle  of  the  thyroid  car- 
tilage around  to  the  anterior  angles  of  the  bases  of  the  arytenoids,  and 
consist  of  two  thin  layers  of  mucous  membrane  covering  the  ligaments 
23 


354  HUMAN   ANATOMY 

named,  each  having  the  thyro-arytenoideus  muscle  external  and  par 
allel  to  it. 

Ventricle  of  the  Larynx  (ventriculus  laryngis)  (7), — is  an  oblong  fossa 
on  each  side  of  the  larynx,  between  the  true  and  false  vocal  cords, 
leading  up  to  the  sacculus  laryngis  by  a  narrow  opening. 

Sacculus  Laryngis  (appendix  ventricuke)  or  Laryngeal  Pouch, — is  a 
membranous  sac,  placed  between  the  superior  vocal  cord  and  the 
thyroid  cartilage.  It  is  of  conical  shape,  and  contains  60  or  70  small 
mucous  glands  which  secrete  a  fluid  for  the  lubrication  of  the  true 
vocal  cord.  The  sacculus  is  covered  in  by  the  aryteno-epiglottideus 
inferior  muscle  internally,  and  by  the  thyro-epiglottideus  externally, 
both  muscles  compressing  it  to  discharge  its  contents.  The  Sacculus 
Laryngis  is  also  called  the  Sinus  of  Morgagni,  and  the  lower  part  of 
the  ventricle  is  sometimes  named  the  Sac  of  Hilton. 

Epithelium, — is  stratified  squamous  epithelium  over  the  true  vocal  cords, 
the  upper  part  of  the  aryteno-epiglottidean  folds,  and  the  upper  half 
of  the  posterior  surface  of  the  epiglottis;  over  all  the  rest  of  the  larynx, 
the  lining  mucous  membrane  is  covered  by  columnar  ciliated  cells. 

Muscles  of  the  Larynx  are  8  in  number,  5  of  which  are  the  muscles  of 
the  vocal  cords  and  rima  glottidis,  and  3  are  connected  with  the  epiglottis. 
The  former  are  the — 

Crico-thyroid  (m.  crico-thyreoideus). 

Crico-arytenoideus  Posticus  (m.  crico-arytaenoideus  posterior). 

Crico-arytenoideus  Lateralis  (m.  crico-arytaenoideus  lateralis). 

Arytenoideus  (m.  arytaenoideus) . 

Thyro-arytenoideus  (m.  thyreo-arytaenoideus). 

Muscles  of  the  Epiglottis  are  the — • 

Thyro-epiglottideus  (m.  thyreo-epiglottideus). 
Aryteno-epiglottideus  (arytaeno-epiglottideus)  Superior  and  Inferior. 

These  muscles  are  described  at  page  85. 

Vessels  of  the  Larynx.  The  Arteries  are  the  Superior  Laryngeal  and 
Crico-thyroid  branches  of  the  superior  thyroid  (a.  thyreoidea  Superior) 
from  the  external  carotid:  and  the  Inferior  Laryngeal  Branch  of  the  infe- 
rior thyroid  (a.  thyreoidea  inferior)  from  the  thyroid  axis  (truncus  thy- 
reocervicalis).  The — 

Veins, — open  into  the  internal  jugular  and  the  innominate  vein. 

Lymphatics, — open  into  glands  near  the  bifurcation  of  the  common  caro- 
tid artery,  and  others  in  front  of  the  crico-thyroid  membrane. 

Nerves  of  the  Larynx  are  the  Superior  and  Recurrent  (inferior)  Laryn- 
geal branches  of  the  pneumogastric  (n.  vagus),  joined  by  filaments  from  the 
spinal  accessory  (n.  accessorius)  and  the  sympathetic.  The — • 


THE  TRACHEA  AND  BRONCHI  355 

Superior  Laryngeal, — is  the  nerve  of  sensation.  It  enters  the  larynx  by  a 
hole"  in  the  thyro-hyoid  membrane,  and  supplies  the  mucous  mem- 
brane, and  the  crico-thyroid  and  arytenoideus  muscles.  It  has  the 
following  branches,  namely— 

External  Laryngeal.  Internal  Laryngeal. 

Recurrent  Laryngeal  (n.  laryngeus  inferior), — is  the  motor  nerve.  It 
winds  from  before  backwards,  around  the  subclavian  artery  on  the 
right  side,  around  the  arch  of  the  aorta  on  the  left  side,  and  is  dis- 
tributed to  all  the  laryngeal  muscles  except  the  crico-thyroid  and 
arytenoideus  giving  off,  in  its  course,  cardiac,  oesophageal,  tracheal, 
and  pharyngeal  filaments,  and  finally  anastomosing  with  the  superior 
laryngeal  nerve. 

THE  TRACHEA  AND  BRONCHI 

The  Trachea  is  a  membrano-cartilaginous,  cylindrical  tube,  about  4% 
inches  long,  and  %  to  i  inch  in  diameter,  beginning  at  the  lower  border 
of  the  larynx,  opposite  the  6th  cervical  vertebra,  and  ending  opposite  the 
upper  border  of  the  5th  thoracic,  by  its  bifurcation  into  the  two  bronchi. 
It  is  composed  of  a  fibro-elastic  membrane  containing  16  to  20  imperfect 
cartilaginous  rings,  connected  by  muscular  fibres.  It  is  lined  with  mucous 
membrane  covered  with  ciliated  columnar  epithelium,  and  furnished  with 
racemose  glands,  the  tracheal  glands. 

Anteriorly, — it  is  convex,  and  is  covered  from  above  downward  by  the — 

Isthmus  of  the  Thyreoid  Gland.  Thymus  Gland. 

Inferior  Thyreoid  Veins.  Arch  of  the  Aorta. 

Sterno-hyoid  Muscle.  Left  Innominate  Vein. 

Sterno-Thyreoid  Muscle.  Innominate  Artery. 

Cervical  Fascia.  Left  Carotid  Artery. 

Manubrium  of  the  Sternum.  Deep  Cardiac  Plexus. 

Posteriorly, — it  is  flat,  and  in  relation  with  the  oesophagus. 
Laterally , — it  is  in  relation  with  the— 

Common  Carotid  Arteries.     Recurrent  or  Inferior  Laryngeal  Nerves. 
Thyreoid  Gland,  lateral  lobes.     Pleurae. 
Inferior  Thyreoid  Arteries.     Pneumogastric  or  Vagus  Nerves. 
The  Bronchi  are  two  tubes  similar  in  formation  to  the  trachea,  extending 
from  its  bifurcation  into  the  lungs,  where  they  divide  and  subdivide  into 
bronchial  tubes  (rami  bronchiales),  losing  their  rings  at  the  2d  or  3d  sub- 
division, whence  plates  of  cartilage  extend  in  their  walls  to  their  minuter 
ramifications.     The — 


356  HUMAN   ANATOMY 

Right  Bronchus  (bronchus  dexter), — the  wider,  and  the  more  hori- 
zontal, is  about  i  inch  long,  has  6  to  8  rings,  and  divides  into  2  main 
divisions,  the  eparterial  branch,  to  the  upper  lobe,  given  off  above  the 
pulmonary  artery,  and  the  hyparterial  branch,  passing  under  the  artery 
to  be  divided  into  two  branches,  for  the  middle  and  lower  lobes.  The 
right  bronchus  lies  behind  the  vena  cava  superior  and  the  right  auricle 
of  the  heart  having  the  right  pulmonary  artery  at  first  below,  then 
anterior  to  it,  and  the  vena  azygos  major  arching  over  it  from  behind 
forward. 

Left  Bronchus, — the  narrower  and  more  oblique,  is  nearly  2  inches  long, 
Has  9  to  12  rings,  and  divides  into  3  main  divisions  (though  its  lung 
has  but  2  lobes).  It  passes  beneath  the  arch  of  the  aorta  and  in  front 
of  its  descending  portion,  also  in  front  of  the  oesophagus  and  the  tho- 
racic duct,  having  the  left  pulmonary  artery  above  and  in  front  of  it. 

Vessels  and  Nerves.  The  Arteries  are  the  Tracheal,  branches  of  the 
inferior  thyreoid,  from  the  thyreoid  axis  (truncus  thyreocervicalis) ;  and 
the  Bronchial,  from  the  thoracic  aorta.  The — • 

Veins, — open  into  the  thyreoid  plexus  and  the  bronchial  veins. 

Lymphatics, — terminate  in  the  mediastinal  glands. 

Nerves, — are  derived  from  the  pneumogastric  (n.  vagus)  and  its  recur- 
rent or  inferior  laryngeal  branch,  also  from  the  sympathetic. 

THE  PLEURA 

The  Pleurae  are  two  delicate  serous  sacs,  one  surrounding  each  lung, 
and  reflected  over  the  pericardium,  the  diaphragm,  and  the  inner  surface 
of  the  thorax.  The  right  sac  is  shorter,  wider,  and  reaches  higher  into  the 
neck  than  the  left.  The  two  sacs  meet  for  a  short  space  behind  the  middle 
of  the  sternum,  at  the  approximation  of  the  anterior  borders  of  the  lungs. 
The— 

Pleura  Pulmonalis,  or  Visceral  Layer, — covers  the  lung,  and  invests  that 

organ  as  far  as  its  root. 
Pleura  Costalis,  or  Parietal  Layer, — lines  the  inner  surface  of  the  parie- 

tes  of  the  chest. 

Cavity  of  the  Pleura, — is  the  space  between  the  two  layers. 
Ligamentum  Latum  Pulmonis,  or  Broad  Ligament  of  the  Lung, — is  a 
triangular  fold  or  reflection  of  pleura,  which  descends  from  the  root 
of  the  lung  posteriorly  to  the  upper  surface  of  the  diaphragm. 
The  Mediastinum  is  the  space  between  the  two  pleurae  in  the  median 
line  of  the  thorax,  extending  from  the  sternum  to  the  vertebral  column, 
and  containing  all  the  thoracic  viscera  except  the  lungs.     The — 


THE   LUNGS  357 

Superior  Mediastinum, — lies  above  the  upper  level  of  the  pericardium 
and  contains  the — 

Origins  of  the  Sterno-hyoid  and  Sterno-thyreoid  Muscles. 
Longus  Colli  Muscles,  their  lower    Pneumogastric  Nerve  (n.  vagus). 

ends.  Cardiac  and  Phrenic  Nerves. 

Arch  of  the  Aorta.  Left  Recurrent  or  Inferior  Laryn- 

Innominate  Artery.  geal  Nerve. 

Left  Carotid  Artery,  in  part.  Trachea. 

Left  Subclavian  Artery,  in  part.     (Esophagus. 
Superior  Vena  Cava,  upper  half.     Thoracic  Duct. 
Innominate  Veins.  Thymus  Gland. 

Left  Superior  Intercostal  Vein.       Lymphatic  Glands. 

Anterior  Mediastinum, — between  the  sternum  and  the  pericardium,  con- 
tains— 

Areolar  Tissue.  Branches  of  Internal  Mammary  Artery. 

Triangularis  Sterni  Muscle.     Lymphatic  Vessels  and  Glands. 

Middle  Mediastinum, — contains  the — • 

Heart  and  Pericardium.  Bifurcation  of  the  Trachea. 

Ascending  Aorta.  Pulmonary  Arteries  and  Veins. 

Superior  Vena  Cava,  lower  half.   Phrenic  Nerves.    Lymphatic  Glands. 
Posterior  Mediastinum, — contains  the — 

Descending  Aorta.  (Esophagus. 

Azygos  Veins.  Thoracic  Duct. 

Pneumogastric  (nn.  vagi)  and  Splanchnic    Lymphatic  Glands. 
Nerves. 

THE  LUNGS  (PULMONES) 

The  Lungs  are  the  two  essential  organs  of  respiration  contained  in  the 
cavity  of  the  thorax,  where  they  are  separated  from  each  other  by  the 
heart  (i)  and  the  other  contents  of  the  mediastinum.  They  are  covered 
by  the  pleurae,  and  are  characterized  by  lightness  (sp.  gr.  0.345  to  0.746), 
sponginess,  elasticity,  and  crepitation  when  pressed.  They  weigh  together 
about  42  ounces,  the  right  lung  being  the  heavier  by  about  2  ounces.  At 
birth  their  color  is  a  pinkish-white,  becoming  mottled  as  age  advances  by 
slate-colored  patches,  from  the  deposit  of  carbonaceous  granules  in  the 
areolar  tissue  of  the  organ.  The.  Right  Lung  is  the  larger  and  has^3  lobes; 
the  Left  Lung  has  2  lobes.  Each  lung  presents  for  examination  an — 

Apex  (apex  pulmonis), — situated  in  the  neck,  behind  the  interval  be- 
tween the  two  heads  of  the  sterno-mastoid  muscle,  and  rising  about 


35« 


HUMAN   ANATOMY 


an  inch  above  the  clavicle.  It  is  in  relation  with  the  subclavian  artery 
and  the  scaleni  muscles. 

Base  (basis  pulmonis), — is  broad,  concave,  and  directed  obliquely  down- 
ward and  backward,  resting  on  the  upper  convex  surface  of  the  dia- 
phragm. 

External  Surface  (facies  costalis), — is  convex,  smooth,  marked  by  the 
fissures,  and  corresponds  in  form  to  that  of  the  thorax. 

Inner  Surface  (facies  mediastinalis), — is  concave,  presents  in  front  a 
depression  for  the  heart  and  behind  a  deep  fissure,  the  hilum,  which 
gives  attachment  to  the  root  of  the  lung. 

FIG.  123. 


Root  (radix  pulmonis), — is  where  the  bronchus  (18),  vessels  (20),  and 
nerves  enter  the  lung,  bound  together  by  areolar  tissue.  In  front  of 
the  root  is  the  phrenic  nerve,  behind  it  the  pneumogastric  nerve  (n. 
vagus).  Its  chief  structures  are  arranged  in  the  following  manner: — 


(Pulmonary  veins. 
Pulmonary  artery. 


From  above  downward,  on 
right  side  of  body, 


Bronchus,  etc. 

Bronchus  (18),  etc. 
Pulmonary  artery. 
Pulmonary  veins  (20). 


V.  A.  B. 


B.  A.  V. 


THE    LUNGS 


359 


From  above  downward,  on 
left  side  of  body, 


Pulmonary  artery  (7). 
Bronchus  (19),  etc. 
Pulmonary  veins  (20). 


A.  B.  V. 


FIG.  124. 


Structure  of  the  Lung.  The  lung  has  a  serous  coat  (the  pleura);  a 
sub-serous,  elastic  areolar  tissue,  investing  the  entire  organ,  and  extending 

inward  between  the  lobules;  and  the 
parenchyma,  or  true  lung-tissue,  com- 
posed of — 

Lobules, — each  consisting  of  several 
air-cells  or  compartments,  arranged 
around  the  termination  of  a  bron- 
chiole, and  surrounded  by  6  plexuses 
of  pulmonary  and  bronchial  arteries 
and  veins,  lymphatics  and  nerves. 
Each  lobule  is  a  miniature  lung, 
pyramidal  in  form,  with  base  out- 
ward, and  about  ^f  2  inch  in  diam- 
eter. Fig.  123  shows  2  lobules. 
Alveoli,  or  Air-cells, — are  separated 
from  each  other  by  thin  septa,  are 
lined  with  pavement  epithelium  on 
a  basement  membrane,  and  vary 
in  diameter  from  ^Oo  to  Ko  inch. 

Vessels  and  Nerves  of  the  Lungs.  The  lungs  are  nourished  by  the 
bronchial  arteries,  and  supplied  with  blood  for  oxygenation  by  the  pul- 
monary arteries. 

Bronchial  Arteries, — are  derived  from  the  thoracic  aorta. 

Bronchial  Veins, — open  on  the  right  side  into  the  vena  azygos  major, 

on  the  left  side  into  the  superior  intercostal  vein. 
Pulmonary  Arteries  (5,  6,  7), — are  derived  from  the  right  heart.     Their 

terminal  (lobular)  branches  do  not  anastomose  with  each  other. 
Pulmonary  Veins  (20), — open  by  4  large  orifices  into  the  left  auricle  of 
the  heart,  carrying  oxygenated  blood  from  the  lungs  to  the  left  heart. 
The  veins  anastomose  freely. 

Lymphatics, — terminate  in  the  bronchial  glands,  at  the  root  of  the  lung. 
Nerves, — are  branches  from  the  vagus  and  the  sympathetic  forming 
the  anterior  and  posterior  pulmonary  plexuses,  from  which  filaments 
are  distributed  to  each  lobule. 


360  HUMAN    ANATOMY 

THE  URINARY  ORGANS 
THE  KIDNEYS  (RENES) 

The  Kidneys  (renes)  are  two  organs,  situated  in  the  back  part  of  the 
abdominal  cavity,  one  on  each  side  of  the  vertebral  column,  behind  the 
peritoneum,  extending  from  the  nth  and  i2th  ribs  to  within  2  inches  of 
the  crest  of  the  ileum,  the^ right  kidney  being  a  little  lower  than  the  left 
one.  Each  kidney  is  about  4  inches  by  2  by  i,  in  the  male  adult  weighs 
from  4)^  to  6  oz.;  and  presents  on  its  inner  concave  border  the — 

U.ilum, — a  fissure  leading  into  the  sinus  or  cavity  of  the  organ,  and  per- 
mitting the  passage  of  the  vessels,  nerves,  and  ureter,  arranged  in  the 
following  order,  from  before  backward,  the  renal  vein,  renal  artery, 
ureter,  ^VAU. 

Relations  of  the  Kidneys.     They  are  partially  covered  by  peritoneum 
on  their  anterior  surface,  but  not  at  all  posteriorly.     They  are  surrounded 
by  a  mass  of  fat  and  areolar  tissue,   and  have  the  following  relations: — 
Anterior  Surface  (facies  renis  anterior)  of  the  Right  Kidney, — is  in  rela- 
tion with  the  supra-renal  gland,  the  right  lobe  of  the  liver,  the  de- 
scending duodenum,  and  the  ascending  colon. 

Anterior  Surface  of  the  Left  Kidney, — with  the  supra-renal  gland,  the 
stomach,  the  tail  of  the  pancreas,  the  descending  colon,  the  jejunum, 
and  part  of  the  spleen. 

Posterior  Surface  (facies  renis  posterior), — with  the  crus  of  the  dia- 
phragm, 1 2th  rib  and  the  transverse  processes  of  the  upper  three 
lumbar  vertebrae,  psoas  magnus,  quadiatus  lumborum,  and  the  apo- 
neurosis  of  the  transversalis  muscle. 
Upper  Extremity  (extremitas  superior), — is  capped  by  the  supra-renal 

capsule  (i). 
Lower  Extremity  (extremitas  inferior), — extends  to  within  2  inches  of 

the  crest  of  the  ilium. 

jGr.eneral  Structure  of  the  Kidney.  A  vertical  section  from  its  convex 
to  its  concave  border,  shows  it  to  consist  of  a  central  cavity  QTsinuSj  sur- 
rounded except  on  one  side  by  the  kidney  substance  proper  (parenchyma) . 
The  latter  is  divided  into  a  cortical  portion  externally,  and  a  medullary 
portion  internally,  the  medullary  being  arranged  in  pyramidal  masses, 
whose  apices  project  into  the  central  cavity.  A  dense,  fibrous  capsule 
(tunica  fibrosa)  invests  the  organ,  and  is  reflected  inward  at  the  hilum, 
lining  the  sinus  and  forming  sheaths  for  the  vessels.  It  gives  off  an  inter- 
stitial stroma  of  connective  tissue,  which  binds  the  vessels  and  tubes  firmly 
together  throughout  the  substance  of  the  kidney.  The — 


THE    KIDNEY  361 

Cynical  Portion, — consists  of  uriniferous  tubules  (tubuli  renales).     Mal- 
pighian  bodies  (glomerula  or  renal  corpuscles),  blood-vessels,  nerves, 
lymphatics,  connective  tissue,  and  a  granular  matrix.     It  is  of  a  red 
p  color,    and  is  prolonged   down    between 

the  pyramids,  to  the  sinus;  the  prolon- 
gations being  named  columns  of  Berlin 
(columnae  renales)  and  the  portions  over 
the  bases  of  the  pyramids  are  the  cortical 
arches. 

Medullary  .Substance  (3), — contains  chiefly 
the  straight,  collecting  portion  of  the 
uriniferous  tubules,  arranged  in  pyram- 
idal masses,  the  pyramids  of  Malpighi 
(pyramides  renales),  the  apices  of  which 
project  into  the  sinus. 

Sinus, — receives  the  pelvis  (6)  of  the  ureter 
(7),  and  is  divided  into  3  infundibula  (5), 
and  they  into  7  to  13  calices,  into  which 
open  the  orifices  of  the  uriniferous  tubules, 
1000  on  each  papilla  or  apex  of  a  pyramid. 

Minute  Structure  of  the  Kidney  commences  in  the  cortical  substance 
of  the  organ  as  the  Malpighian  bodies  (corpuscula  renis),  small  round 
masses  of  deep-red  color,  averaging  about  K20 
inch  in  diameter,  and  each  consisting  of  a  central 
glomerulus  of  vessels  and  a  membranous  envelope 
(capsula  glomeruli)    or    Bowman's   capsule,   the 
latter  being  the  commencement  of  a  uriniferous 
tubule.     The— 

Malpighian.  Tuft, — or  vascular  glomerulus,  is  a 
network  of  convoluted  capillary  blood-vessels, 
beginning  by  the  afferent  vessel  and  ending  in 
the  eferent  vessel,  which  are  the  respective 
radicles  of  some  of  the  branches  of  the  renal 
artery  (a)  and  the  renal  vein  (»).  The  affer- 
ent vessels  are  usually  the  larger. 
Bowman's  Capsule  (capsula  glomeruli)  (c), — 
surrounding  the  glomerulus,  is  the  dilated 

extremity  of  a  uriniferous  tubule  (d),  and  is  lined  on  its  inner  surface 
by  a  layer  of  j>quamous  epithelial  cells,  on  a  delicate  supporting 
membrane,  closely  surrounding  the  convolutions  of  the  glomerulus 
and  dipping  in  between  them. 


362  HUMAN   ANATOMY 

The  Tubuli  Renales,  or  Uriniferous  Tubules,  begin  at  the  capsule  of 
Bowman  in  the  Malpighian  bodies,  and  open  into  the  sinus  of  the  kidney 
by  orifices  on  the  surface  of  the  papillae.  During  their  course  they  leave 
the  cortical  portion,  enter  the  medullary  portion,  return  to  the  cortical 
and  again  to  the  medullary,  in  which  they  continue  to  their  termination. 
In  their  course  they  become  first  convoluted,  then  spiral,  then  looped, 
again  spiral  and  convoluted,  curved  and  finally  straight;  and  have  received 
the  following  names: — • 

Proximal  Convoluted  Tube, — the  first  portion,  below  the  neck  at  Bow- 
man's capsule,  in  the  cortical  zone.     Epithelium  lining  the  tube  is 
polyhedral  and  of  striated  appearance. 
Spiral  Tube  of  Schachowa, — in  the  cortical  zone.     Epithelium  polyhedral 

and  striated. 

Henle's  Loop, — in  the  medullary  zone,  consists  of  a  descending  limb,  a 
loop,  and  an  ascending  limb,  the  latter  becoming  spiral- as  it  ascends 
into  the  cortical  zone.  Epithelium  flat  in  the  descending  limb,  poly- 
hedral and  striated  in  the  ascending  one. 

Irregular  Tubule, — in  the  cortical  zone.  Epithelium  angular  and  stri- 
ated. 

Distal  Convoluted  Tubule, — in  the  cortical  zone.     Epithelium  polyhedral. 
Curved    Tube, — in    the    cortical    zone.     Epithelium    varied,    angular, 

spindle-shaped,  polyhedral. 

Straight  or  Collecting  Tube, — partly  in  the  cortical  zone,  descends 
through  the  medullary  portion  and  joins  with  others,  forming  the 
pyramids  of  Fcrrein  (apices  outward)  in  the  cortical  zone,  and  the 
pyramids  of  Malpighi  (apices  inward)  in  the  medullary  substance. 
Epithelium  more  or  less  columnar. 

Connective  Tissue  or  Stroma, — binds  the  tubules  firmly  together. 
Arteries  of  the  Kidney  arise  from  the  renal  artery,  a  large  branch  of 
the  abdominal  aorta.     It  divides  into  4  or  5  branches,  which  enter  the 
kidney  at  the  hilum  (hilus  renis),  giving  off  small  branches  to  the  supra- 
renal capsules,  the  ureter,  etc.     These  again  divide  and  end  in  the — 
Arteries  Pro  price  Renales, — the  renal  arteries  proper,  which  enter  the 
kidney  substance  in  the  columns  of  Bertin  (see  page  360),  form  arterial 
arches  over  the  bases  of  the  pyramids,  and  divide  into  ascending  and 
descending  branches.     The — 

Ascending  or  Interlobular  Branches, — pass  to  the  capsule  and  end  in  the 
capillary  network  of  that  part  of  the  cortex,  giving  off  in  their  course 
the  afferent  vessels  to  the  Malpighian  tufts  (see  page  360). 
Descending  or  Arteriolce  Reclce, — supply  the  medullary  pyramids  and 
end  at  their  apices  in  the  venous  plexuses  there  situated. 


' 


THE    URETERS  363 

Veins  of  the  Kidney  arise  from  3  sources, — the  stellate  veins  beneath 
t  he  i -upside  of  the  organ,  the  venous  radicles  in  the  Malpighian  tufts,  and 
the  venous  plexuses  at  the  apices  of  the  pyramids  of  Malpighi.  Those 
from  the  stellate  plexuses  on  the  surface  of  the  kidney  join  together,  form- 
ing the — 

Interlobular  Veins, — which  pass  inward  between  the  pyramids  of  Ferrein, 
receive  branches  from  the  plexuses  on  the  convoluted  urinif  erous  tubes, 
and  join  with  the  vence  recta  from  the  apices  of  the  pyramids  of  Mal- 
pighi, to  form  the — • 

Vence  Propice  Renales, — the  renal  veins  proper,  accompany  the  arteries 
of  the  same  name,  receive  the  efferent  vessels  from  the  Malpighian 
bodies  adjacent,  and  join  with  corresponding  veins  in  the  sinus  to 
form  the — 

Renal  Vein, — emerges  at  the  hilum  and  opens  into  the Jnferior  vena 
cava;  the  left  vein  being  longer  than  the  right,  having  to  cross  in  front 
of  the  abdominal  aorta. 

Nerves  of  the  Kidney  are  derived  from  the  renal  plexus,  which  is 
formed  by  branches  from  the  solar  plexus  (plexus  cceliacum),  the  aortic 
plexus,  the  semilunar  ganglion,  and  the  lessei  and  smallest  splanchnic 
nerves.  They  have  small  ganglia  upon  them,  and  communicate  with  the 
spermatic  plexus. 

Lymphatics  consist  of  a  superficial  and  a  deep  set,  and  terminate  in  the 
lumbar  glands. 

THE  URETERS 

The  Ureter,  the  excretory  duct  of  the  kidney,  is  a  musculo-membranous 
tube,  which  conducts  the  urine  from  the  kidney  to  the  bladder.  It  com- 
mences within  the  sinus  of  the  kidney  by  7  to  13  short  tubes  or  calices, 
which  encircle  the  apices  of  the  pyramids  of  Malpighi,  and  converge  into 
2  or  3  tubular  divisions  or  infundibula,  these  by  their  junction  forming  the 
pelvis  or  upper  dilated  extremity  of  the  duct.  The — 

Ureter  Proper, — begins  at  the  lower  end  of  its  pelvis,  is  about  16  inches 
long,  and  of  the  diameter  of  a  small  goose-quill.  It  descends,  through 
the  lumbar  region  of  the  abdomen  and  the  pelvic  cavity,  to  the  base 
of  the  bladder,  and  opens  into  the  cavity  of  that  organ  about  2  inches 
from  its  fellow. 

Course  of  the  Ureter.  In  its  course  the  ureter  passes  obliquely  down- 
ward and  inward  through  the  lumbar  region,  and  downward,  inward  and 
forward  through  the  pelvic  cavity,  enters  the  posterior  false  ligament  of 
the  bladder,  passes  obliquely  between  the  muscular  and  mucous  coats  of 


364  HUMAN   ANATOMY 

that  organ  for  nearly  an  inch,  and  ends  by  a  constricted  orifice  at  one  of 
the  posterior  angles  of  the  trigone  at  the  base  of  the  bladder. 

Relations  of  the  Ureter.  The  junction  of  the  renal  pelvis  and  the 
ureter  proper  is  opposite  the  spinous  process  of  the  first  lumbar  vertebra, 
about  2  inches  from  the  middle  line  of  the  back.  The  ureter  lies  upon  the 
psoas  muscle  and  behind  the  peritoneum;  behind  the  ileum  on  the  right 
side  and  the  sigmoid  flexure  of  the  colon  on  the  left  side.  It  crosses  the 
common  or  the  external  iliac  artery;  and  is  crossed  by  the  spermatic  vessels, 
and  the  branches  of  the  mesenteric  arteries,  also  by  the  vas  deferens  in  the 
male.  The  right  ureter  lies  close  to  the  outer  side  of  the  inferior  vena 
cava.  In  the  female  the  ureters  pass  along  the  sides  of  the  neck  of  the 
uterus  and  the  upper  part  of  the  vagina,  and  beneath  the  root  of  the  broad 
ligament. 

Structure  of  the  Ureter.     It  is  composed  of  3  coats, — fibrous,  muscular, 
and  mucous.     The  fibrous  coat  (tunica  adventitia)  is  continuous  with  the 
capsule  of  the  kidney  and  with  the  fibrous  structure  of  the  bladder.     The — 
Muscular  Coat  (tunica  muscularis), — consists  of  longitudinal  fibres  ex- 
ternally (stratum  externum),  and  circular  fibres  internally  (stratum 
medium).     A  third  layer  (stratum  internum),  consisting  of  longi- 
tudinal fibres,  is  found  internal  to  the  circular  layer,  in  the  neighbor- 
hood of  the  bladder. 

Mucous  Coat, — is  prolonged  over  the  papillae  of  the  kidney,  and  is  con- 
tinuous with  the  mucous  lining  of  the  bladder.  Its  epithelium  re- 
sembles that  of  the  bladder,  and  is  known  as' 'transitional  epithelium, 
consisting  of  3  layers  of  cells,  the  innermost  of  which  are  quadrilateral 
in  shape. 

Vessels  and  Nerves.  The  Arteries  of  the  ureter  are  branches  from  the 
renal,  spermatic,  internal  iliac,  and  inferior  vesical.  The  Nerves  are  de- 
rived from  the  inferior  mesenteric,  spermatic,  and  pelvic  plexuses. 

THE  SUPRA-RENAL  GLANDS  OR  CAPSULES  (GLANDULE 
SUPRARENALES) 

The  Supra-renal  Glands  are  properly  classed  with  the  ductless  glands 
of.  the  chromaphiL^and  cortical  systems  (see  page  344).  They  are  two 
small,  yellowish  bodies,  situated  one  above  each  kidney,  behind  the  perit- 
oneum, and  in  the  posterior  portion  of  the  abdomen.  They  vary  in  size 
in  different  individuals,  but  are  usually  i^  inches  long  and  wide,  and  from 
2  to  3  lines  in  thickness.  Each  capsule  has  a  small  furrow,  the  hilum,  on 
its  anterior  surface,  in  which  the  vessels  enter  the  organ,  and  in  structure 
consists  of  a — 


THE  BLADDER  365 

Fibrous  Capsule, — which  is  very  thin,  closely  adherent,  and  sends  numer- 
ous septa  inward. 

Cortical  Substance, — composed  of  columnar  masses  of  polyhedral  cells, 
held  together  in  layers  by  a  fibrous  stroma. 

Medullary  Substance, — is  darker  than  the  cortical  portion,  and  pulpy. 
It  consists  of  granular  cells,  supported  by  a  delicate  stroma,  and 
believed  by  some  anatomists  to  be  prolonged  into  the  nerve  fibres  of 
a  very  intricate  plexus. 

Relations  of  the  Supra-renal  Glands.  Their  surface  is  surrounded  by 
ireolar  tissue  containing  much  fat;  their  bases  rest  on  the  upper  front 
parts  of  the  kidneys,  theiVgpsterior  surfaces  on  the  crura  of  the  diaphragm, 
about  the  level  of  the  loth  thoracic  vertebra.  The — 

A  nterior  Surface, — of  the  right  gland  is  covered  by  the  liver;  that  of  the 
Ic-ft  one  by  the  spleen  and  pancreas. 

Superior  Surface, — of  each  is  in  relation  internally  with  the  great  splanch- 
nic nerve  and  semilunar  ganglion. 

Vessels  and  Nerves.  The  Arteries  are  the  Supra-renal  branches  of  the 
aorta,  renal,  and  phrenic  arteries,  forming  a  dense  capillary  plexus  in  the 
cortical  portion  of  the  organ. 

Veins, — of  each  open  into  a  single  trunk,  the  Supra-renal  Vein,  which 
on  the  right  side  of  the  body  empties  into  the  inferior  vena  cava,  on 
the  left  side  into  the  left  renal  vein. 

Lymphatics, — open  into  the  lumbar  glands. 

Nerves, — are  derived  from  the  solar  (cceliac)  and  renal  plexuses,  with 
some  filaments  from  the  phrenic  and  vagus  nerves,  forming  a  compli- 
cated network  in  the  medullary  substance  of  the  organ,  and  having 
numerous  small  ganglia  developed  upon  them. 


THE  BLADDER  (VESICA  URINARIA) 

The  Bladder,  the  reservoir  for  the  urine,  is  a  musculo-membranous  sac, 
situated  in  the  anterior  portion  of  the  pelvis,  behind  the.  pubes,  and  in 
front  of  the  rectum  in  the  male,  in  front  of  the  cervix  uteri  and  Vagina  in 
the  female.  When  empty  and  contracted,  or  when  slightly  distended,  it  is 
contained  in  the  pelvic  cavity;  when  greatly  distended  it  is  ovoid  in  shape, 
and  rises  into  the  abdominal  cavity,  often  extending  nearly  as  high  as  the 
umbilicus.  When  moderately  distended  it  measures  about  5  by  3  inches, 
and  holds  about  a  pint.  The — 

Summit, — is  connected  to  the  umbilicus  by  the  urachus  (ligamentum 
umbilicale  medium)  and  the  obliterated  hypogastric  arteries  (liga- 


366 


HUMAN   ANATOMY 


FIG.  127. 


menta  umbilicales  laterales)  of  the  foetus,  forming  three  fibrous  cords, 
the  Superior  Ligament  of  the  bladder. 

Superior  or  Abdominal  Surface, — is  free,  and  is  covered  by  peritoneum. 

Anterior  or  Pubic  Surface, — is  partly  covered  by  peritoneum  above,  and 
is  in  relation  below  with  the  internal  obturator  muscles,  the  recto- 
vesical  fascia,  and  the  anterior  true  ligaments  of  the  bladder. 

Posterior  Surface, — is  covered  by  peritoneum,  and  is  in  relation  with  the 
rectum  in  the  male,  with  the  uterus  and  upper  part  of  the  vagina  in 
the  female. 

Lateral  Surfaces, — are  partly  covered  by  peritoneum  behind  and  above; 
each  is  crossed  obliquely  by  the  obliterated  hypogastric  artery  and  the 
vas  deferens  (c),  the  first  passing  from 
below  forward,  the  latter  from  below 
backward. 

Fundus  or  Base, — is  partly  covered  by 
peritoneum,  and  rests  on  the  second 
portion  of  the  rectum  in  the  male,  on 
the  lower  part  of  the  cervix  uteri  and 
adherent  to  the  anterior  wall  of  the 
vagina  in  the  female. 

Cervix  or  Neck, — is  constricted  and  contin- 
uous with  the  urethra  (f).  It  is  sur- 
rounded in  the  male  by  the  prostate 
gland  (h),  and  is  directed  downward 
and  forward. 

Ligaments  of  the  Bladder  are  10  in  num- 
ber, of  which  5  are  true  ligaments,  and  5 
formed  by  folds  of  peritoneum.  The  true  ligaments  are  the — 

Anterior  or  Pubo-prostatic,  2, — are  formed  by  the  recto-vesical  fascia, 
and  extend  from  the  neck  of  the  bladder,  over  the  prostate  gland,  to 
the  back  of  the  pubic  bone. 

Lateral,  2, — also  formed  by  the  recto-vesical  fascia,  are  attached  to  the 
sides  of  the  base  of  the  bladder,  and  the  prostate  gland. 

Urachus, — the  superior  ligament  (ligamentum  umbilicale  medium), 
connects  the  summit  of  the  bladder  with  the  umbilicus.  It  is  the 
obliterated  remains  of  a  canal,  which  in  the  embryo  connects  the 
bladder  with  the  allantois  and  is  situated  between  the  two  obliter- 
ated hypogastric  arteries  (ligamenta  umbilicales  laterales). 
False  Ligaments,  folds  of  peritoneum,  are  the — 

Posterior  False  Ligaments  (plicae  vesico-uterinae)  female,  (plicae  recto- 
vesicalis)  male,  2, — pass  from  the  postero-lateral  parts  of  the  bladder. 


are  false  ligaments,  being 


THE  BLADDER  367 

to  the  sides  of  the  rectum  in  the  male,  to  the  sides  of  the  uterus  in 
the  female. 

Lateral  False  Ligaments  (plicae  umbilical es  laterales),  2, — from  the 
iliac  fossae  and  lateral  walls  of  the  pelvis  to  the  sides  of  the  bladder. 

Superior,  or  Suspensory  Ligament  (plica  umbilicalis  media), — from  the 
summit  of  the  bladder  to  the  umbilicus,  being  peritoneum  carried 
off  from  the  bladder  by  the  urachus  and  the  obliterated  hypogastric 
arteries. 

Interior  of  the  Bladder  is  lined  by  mucous  membrane,  which  forms 
folds  or  ruga  when  the  viscus  is  empty,  being  loosely  connected  to  the 
muscular  coat,  except  at  the  trigone  and  the  uvula,  where  it  is  closely  ad- 
herent. The  floor  of  the  bladder  presents  the — 

Trigonum  Vesica,  or  Vesical  Trigone  (i,  Fig.  127), — a  pale-colored,  tri- 
angular space,  extending  from  the  urethral  opening  in  front  to  a  line 
connecting  the  orifices  of  the  ureters  behind;  and  characterized  by  its 
smooth  surface  and  the  intimate  adhesion  between  its  mucous  and 
muscular  coats. 

Uvula  Vesicce  (3,  Fig.  127), — is  a  small  elevation  of  mucous  membrane 
projecting  from  the  floor  of  the  bladder  into  the  urethral  orifice.  It  is 
said  to  be  lifted  by  the  anterior  fibres  of  the  levator  ani  muscle. 

Orifices  of  the  Ureters  (2,  Fig.  127), — about  2  inches  apart,  at  the  base  of 
the  trigone,  and  i  ^  inches  from  the  urethral  opening. 

Structure  of  the  Bladder.  The  bladder  has  4  coats, — serous  or  perit- 
oneal, muscular,  sub-mucous,  and  mucous.  The  peritoneal  coat  is  a 
partial  one,  investing  only  the  superior  and  posterior  surfaces,  and  the 
upper  portion  of  the  lateral  surfaces.  The — 

Muscular  Coat, — consists  of  unstriped  muscular  fibres,  arranged  in  3 
layers;  an  external  layer,  chiefly  longitudinal,  the  so-called  detrusor 
urines  muscle;  a  middle  layer,  mostly  circular,  and  forming  a  sphincter 
vesicfg  around  the  neck;  and  an  internal  layer,  chiefly  longitudinal. 

Muscles  of  the  Ureters, — are  two  bands  of  oblique  fibres,  extending  from 
behind  the  orifices  of  the  ureters  to  the  middle  lobe  of  the  prostate 
gland. 

Sub-mucous  Coat, — is  a  layer  of  areolar  tissue,  connecting  the  muscular 
with  the  mucous  coat. 

Mucous  Coat, — is  thin,  smooth,  of  a  pale  rose  color,  and  is  continuous 
with  the  lining  membrane  of  the  ureters  and  the  urethra.  Its  epithe- 
lium is  of  the  transitional  variety,  consisting  of  an  inner  layer  of  poly- 
hedral, flattened,  nucleated  cells;  beneath  which  are  two  layers  of 
club-shaped  and  spindle-shaped  cells,  wedged  together.  It  contains 
no  mucous  glands. 


368  HUMAN   ANATOMY 

Vessels  and  Nerves.  The  Arteries  of  the  bladder  are  the  superior 
middle,  and  inferior  Vesical  in  the  male,  with  additional  branches  from  the 
uterine  and  vaginal  in  the  female;  all  from  the  anterior  trunk  of  the  internal 
iliac.  The— 

Veins, — form  a  plexus  around  the  neck,  sides,  and  base  of  the  bladder, 

and  terminate  in  the  internal  iliac  vein. 
Lymphatics, — terminate  in  the  internal  iliac  glands. 
Nerves, — are  derived  from  the  pelvic  plexus  to  the  upper  part  of  the 
organ,  from  the  3d  and  4th  sacral  nerves  to  its  base  and  neck. 

THE  MALE  URETHRA 

The  Urethra  is  the  urinary  canal  from  the  neck  of  the  bladder  to  the 
meat  us  urinarius;  in  the  male  it  is  chiefly  within  the  penis,  is  from  8  to  9 
inches  in  length,  and  is  divided  into  three  parts, — the  pr astatic,  membranous, 
and  spongy  portions  of  the  urethra. 

The  Prostatic  Portion  (pars  prostatica)  of  the  Urethra  is  that  part  of  the 
canal  which  pierces  the  prostate  gland  (4),  is  about  i  finches  in  length,  of 
spindle  shape,  and  the  widest  and  most  dilatable  part  of  the  urethra.  Its 
floor  presents  the — 

Verumontanum,  or  Caput  Gallinaginis  (colliculus  seminalis)    (6), — an 

elevation  of  the  mucous  membrane  (crista  urethralis)  and  its  adjacent 

tissue,  Y±  inch  long,  and  supposed  to  contain  muscular  and  erectile 

tissue. 

Prostatic  Sinus  (7), — one  on  each  side  of  the  verumontanum,  containing 

the  orifices  of  the  prostatic  ducts. 

Sinus  Pocularis,  or  Uterus  Masculinus  (utriculus  prostaticus)  (5), — is  a 

small  cul-de-sac  situated  at  the  front  part  of  the  verumontanum. 

It  extends  for  ^  inch  upward  and  backward  into  the  prostate  gland 

beneath  its  middle  lobe. 

Orifices  of  the  Ejaculatory  Ducts  (8), — open  on  the  margins  of  the  sinus 

pocularis. 

The  Membranous  Portion  (pars  membranacea)  (9)  is  %  inch  long  above, 
and  Yz  inch  along  its  floor,  being  that  part  of  the  canal  lying  between  the 
superior  and  inferior  layers  of  the  triangular  ligament  of  the  perinaeum. 
Its  walls  are  very  thin,  and  almost  destitute  of  erectile  tissue.  It  is 
surrounded  by  the  deep  transversus  perinei  or  compressor  urethras  muscle, 
and  except  the  orifice,  is  the  narrowest  part  of  the  urethral  canal.  On 
its  sides  are  the — 

Ducts  of  Cowper's  Bulbo-urethral  Glands  (n), — on  their  way  to  open 
into  the  bulb  of  the  urethra. 


THE    URETHRA 


369 


FIG.  128. 


The  Cavernous  or  Spongy  Portion  (pars  cavernosa)  (16)  is  about  6 
inches  long,  and  has  two  dilatations,  one  at  each  end,  named  respectively 
the  Bulb  and  the  Fossa  Navicularis.  The — 

Bulb'  of  the  Urethra  (13), — is  the  upper  end  of  the  cavernous  portion, 
projects  backward  for  Y±  inch,  and  contains  the  orifices  (15)  of  the 

ducts  of  the  bulbo-urethral 
or  Cowper's  glands. 
Fossa  Navicularis, — is  the  lower 
dilatation  of  the  urethra, 
and  is  situated  within  the 
glans  penis. 

Lacuna  Magna  (lacuna  ure- 
thralis  of  Morgagni), — the 
largest  of  several  orifices  of 
mucous  follicles,  situated  on 
the  roof  of  the  fossa  navicu- 
laris. 

Glands  of  Littre  (glandulae  ure- 
thrales), — are  numerous  mu- 
cous glands  and  follicles, 
opening  into  the  urethral 
canal,  their  orifices  being 
directed  forwards. 
Meatus  Urinarius, — the  exter- 
nal orifice;  is  the  most  con- 
tracted portion  of  the  ure- 
thra, and  presents  a  vertical 
slit,  about  3  lines  long, 
bounded  laterally  by  two 
small  labia. 

Structure  of  the  Urethra. — It  is 
composed  of  a  continuous  mucous 
membrane,  continuous  with   the 
mucous    lining    of   the   bladder, 
ureters,    and   kidneys,   and   pro- 
longed into  the  ducts  opening  into  the  urethra.     The  mucous  membrane 
is  supported  by  a  submucous  tissue,  which  connects  it  with  the  various 
structures  through  which  it  passes.     The — 

Submucous  Tissue, — consists  of  a  vascular  erectile  layer,  outside  which  is 

a  circular  layer  of  unstriped  muscular  fibres. 

Voluntary  Muscles  of  the  Urethra, — are  the  deep  transversus  perinei  or 
24  •   . 


37O  HUMAN   ANATOMY 

compressor  urethrae  and  the  bulbo-cavernosus  or  accelerator  urinae, 
described  on  page  98. 

Epithelium, — is  of  the  columnar  variety,  except  near  the  meatus  where  it 
is  squamous. 

THE  FEMALE  URETHRA 

The  Urethra  in  the  female  is  only  about  i  ^  inches  long,  imbedded  in  the 
anterior  wall  of  the  vagina,  perforating  the  triangular  ligament,  and  sur- 
rounded by  fibres  of  the  deep  transversus  perinei  or  compressor  urethras 
muscle.  Its  diameter  is  about  %  inch,  but  it  is  capable  of  considerable 
dilatation,  being  surrounded  by  softer  structures  than  are  those  around 
the  male  urethra.  The — 

Meatus  Urinarius, — is  situated  directly  in  front  of  the  vaginal  opening 
and  about  an  inch  behind  the  glans  clitoridis. 

ORGANS  OF  GENERATION 

THE  MALE  ORGANS  OF  GENERATION 
THE  URETHRAL  GLANDS 

The  Prostate  Gland  (prostata)  is  a  musculo-glandular  organ,  which 
surrounds  the  neck  of  the  male  bladder  and  the  beginning  of  the  male 
urethra.  It  is  situated  in  the  pelvic  cavity,  behind  the  lower  part  of  the 
symphysis  pubis,  and  above  the  deep  layer  of  the  triangular  ligament,  its 
posterior  surface  resting  on  the  rectum.  It  is  perforated  by  the  urethra 
and  the  common  seminal  ducts,  but  its  own  ducts  open  into  the  prostatic 
portion  of  the  urethra.  It  measures  about  i%  inches  by  i)^  inches  by  i 
inch,  weighs  about  %  oz.,  resembles  a  horse-chestnut  in  size  and  shape, 
and  consists  of  three  lobes,  two  being  lateral  and  of  equal  size,  the  third  or 
middle  lobe  being  a  small  prominence  situated  in  the  notch  between  the 
lateral  lobes.  Its— 

Position, — is  maintained  by  the  anterior  or  pubo-prostatic  ligaments  of 
the  bladder,  the  deep  layer  of  the  triangular  ligament,  and  the  anterior 
portions  of  the  levator  ani  muscles. 

Structure, — is  glandular  substance  arranged  in  follicular  pouches,  and 

dense  muscular  tissue,  the  whole  being  invested  by  a  firm  fibrous 

capsule,  which  gives  off  thin  trabeculae  into  the  substance  of  the  gland. 

Ducts, — are  1 2  to  20  in  number,  lined  by  columnar  epithelium,  and  open 

on  the  floor  of  the  prostatic  portion  of  the  urethra. 
Arteries, — are  derived  from  the  internal  pudic,  vesical  and  haemorrhoidai 
arteries. 


THE   PENIS  371 

Veins, — terminate  in  the  internal  iliac  vein. 
Nerves, — are  branches  from  the  pelvic  or  hypo-gastric  plexus. 
Cowper's  Glands  (glandulae  bulbo-urethrales)  are  two  small,  rounded 
bodies,  about  the  size  of  peas,  situated  between  the  two  layers  of  the 
triangular  ligament,  one  on  each  side  of  the  membranous  portion  of  the 
urethra,  close  above  the  bulb,  and  enclosed  by  the  transverse  fibres  of  the 
compressor  urethrae  muscle.     The — 

Excretory  Duct, — of  each  gland  opens  by  a  minute  orifice  on  the  floor 
of  the  bulbous  part  of  the  cavernous  portion  of  the  urethra,  after  tra- 
versing the  wall  of  the  urethra  for  about  i  inch,  beneath  its  mucous 
coat. 

THE  PENIS 

The  Penis  is  composed  of  a  mass  of  erectile  tissue  enclosed  in  three 
cylindrical  compartments,  each  surrounded  by  a  fibrous  sheath  which  is 
prolonged  inward,  forming  numerous  bands  or  trabeculae,  which  divide 
the  compartments  into  a  number  of  spaces.  The  compartments  are  the 
two  corpora  cavernosa  and  the  corpus  spongiosum  (corpus  5cavernosum 
urethrae)  (6),  the  latter  lying  between  and  beneath  the  former,  like  the 
ramrod  of  a  double-barreled  gun.  The — 

Erectile  Tissue, — is  lodged  in  the  interspaces  between  the  trabeculae  of 
the  fibrous  structure,  and  consists  of  an  intricate  venous  plexus, 
supplied  by  afferent  arteries  and  emptied  by  efferent  veins. 
The  Corpora  Cavernosa  lie  side  by  side,  forming  the  upper  and  lateral 
parts  of  the  penis.     They  are  joined  together  along  their  anterior  three- 
fourths,  their    posterior    one-fourth  forming  the 
Crura,   which  arise  from  the   tuberosities  of  the 
ischia  and  their  rami,  and  meet  beneath  the  sym- 
physis  pubis,   forming   two   grooves,   one  above 
for  the  dorsal  vessels  (i),  and  nerves  (3),  the  in- 
ferior one  for  the  corpus  spongiosum  (6). 

Suspensory  Ligament  (lig.  suspensorium  penis), 
— a  fibrous  membrane  which  connects  the 
root  of  the  organ  to  the  symphysis  pubis. 
Septum  Pectiniforme  (5), — is  the  front  portion 
of  the  fibrous  septum  between  the  corpora  cavernosa.  This  septum 
extends  but  two-thirds  along  the  penis,  and  is  wanting  for  its  anterior 
third. 

The  Corpus  Spongiosum  (corpus  cavernosum  urethras)  (6)  is  an  erectile 
tube  lying  in  the  inferior  groove  between  the  two  corpora  cavernosa, 
having  within  it  the  urethra,  and  expanded  at  both  ends  to  form  the  glans 


372  HUMAN    ANATOMY 

penis  and  the  bulb.     It  is  composed  of  trabecular  (band-like)  structure, 
derived  from  a  fibrous  sheath,  and  containing  erectile  tissue.     The — 
Bulb  of  the  Corpus  Spongiosum  (bulbus  urethras), — receives  the  urethra 

and  is  surrounded  by  the  (bulbo-cavernosus)  or  accelerator  urinas 

muscle. 
Glans  Penis, — is  the  external   expansion  of  the  corpus    spongiosum 

(corpus  cavernosum  urethras)  and  covers  by  its  base  the  ends  of  the 

two  corpora  cavernosa.     Its  base  presents  a  rounded  border,  called 

the  corona  glandis,  behind  which  is  a  deep  sulcus,  the  cervix  (collum 

glandis). 
Glands  of  Tyson, — small  lenticular  sebaceous  glands  opening  on  the 

corona  and  cervix  of  the  glans,  and  secreting  an  odorous  sebaceous 

matter,  the  smegma. 
Meatus  Urinarius, — the  external  orifice  of  the  urethra,  is  situated  at  the 

summit  of  the  glans  penis. 
Prepuce  (praeputium), — a  prolongation  of  the  integument  of  the  penis, 

covering  or  partly  covering  the  glans  penis. 
Franum  Pmputii  (fraenulum  praeputii), — a  fold  of  mucous  membrane 

lying  along  the  raphe  of  the  glans  penis,  and  connecting  the  prepuce 

with  the  glans. 

Vessels  and  Nerves.  The  Arteries  are  branches  of  the  internal  pudic, 
named  as  follows:  the  artery  of  the  bulb,  to  the  bulb  of  the  corpus  spongio- 
sum; the  arteries  of  the  corpora  cavernosa,  to  that  structure;  and  the  dorsal 
artery  of  the  penis,  to  the  integument  and  fibrous  sheath  of  the  corpora 
cavernosa,  the  glans  and  prepuce.  The — 

Helicine  Arteries, — are  vine-like  branches,  which  project  into  the  cavern- 
ous spaces,  and  are  most  abundant  in  the  back  part  of  the  corpora 

cavernosa. 
Veins, — empty  into  the  dorsal  vein  of  the  penis  and  the  prostatic  venous 

plexus.     They    form   intricate  and  well-developed  plexuses  in  the 

erectile  tissue. 
Lymphatics, — the  superficial  terminate  in  the  inguinal  glands;  the  deep 

join  the  deep  lymphatics  of  the  pelvis. 
Nerves, — are  derived  from  the  internal  pudic  nerve,  and  the  pelvic  or 

hypogastric  plexus  of  the  sympathetic. 

THE  TESTES 

The  Testes  or  Testicles  are  the  glandular  organs  which  secrete  the 
seminal  fluid, — two  oval  bodies  suspended  obliquely  in  the  scrotum  by  the 
spermatic  cords,  each  measuring  about  an  inch  in  diameter,  and  weighing 


THE    TESTES 


373 


Their  coverings,  from  without  inward,  are  6  in  number, 


Scrotum  (see  Fig.  131). 


FIG.  130. 


%  oz.  to  an  ounce, 
as  follows: — 

Skin  (4), — of  the  scrotum. 

Dartos  (5), — the  vascular  tunic. 

Inter  columnar  Fascia, — the  external  spermatic  fascia  (6,  Fig.  131). 

Cremasteric  Fascia  (7,  Fig.  131), — muscular  fibres,  the  cremaster  muscle, 

derived  from  the  lower  border  of  the  internal  oblique  muscle. 
Infundibuliform  Fascia  (9,  Fig.  131), — internal  spermatic  fascia,  or  fascia 

propria;  a  continuation  downward  of  the  transversalis  fascia. 
Tunica  Vaginalis, — the  serous  covering,  originally  a  process  of  the  perit- 
oneum (see  below). 

The  Scrotum  is  a  cutaneous  pouch,  consisting  of  2  layers — the  in- 
tegument and  the  Dartos;  the  latter  being  a  contractile  vascular  tunic, 
continuous  with  the  superficial  fascia  of  the 
thighs  and  perinaeum,  and  forming  a  septum  in 
the  scrotum  between  the  two  cavities  for  the 
testes. 

The  Epididymis  is  an  appendix  to  the  testicle, 
lying  along  its  posterior  border,  and  consists  of  a 
single  'duct  about  20  feet  in  length  when  unraveled, 
but  which  is  wound  upon  itself  so  as  to  occupy  a 
very  small  space.  The — 

Head  or  Globus  Major  (7), — is  formed  by  the 
coni  vasculosi,  or  efferent  ducts   (6)  of  the 
testis,  which  therein  open  into  the  single  duct 
which  forms  the  epididymis. 
Body  (8), — is  formed  by  the  convolutions  of  the 
tube,  held  together  by  fine  connective  tissue. 
Tail  or  Globus  Minor  (9), — the  lower  expanded 
portion,  similarly  formed,  and   connected   to 
the  testis  by  cellular  tissue. 
Vas  or  Ductus  Aberrans  (n), — a  narrow  tube, 
sometimes  found  opening  into  the  canal  of 
the  epididymis  near  its  lower  end,  and  ending  in  a  blind  extremity. 
Hydatids  of  Morgagni  (appendices  testis), — small  pedunculated  bodies, 
found  attached  to  the  epididymis  or  to  the  upper  end  of  the  testicle. 
One  of  them  is  believed  to  be  the  remains  of  the  duct  of  Muller. 

Tunics  of  the  Testis  are  3  in  number, — the  tunica  vaginalis,  or  serous 
covering,  externally;  the  tunica  albuginea,  or  fibrous  covering,  in  the 
middle;  and  the  tunica  vasculosa,  or  pia  mater  testis,  internally.  The — 


374 


HUMAN   ANATOMY 


FIG.  131. 


Tunica  Vaginalis,  the  serous  covering, — has  a  visceral  layer  (n)  (tunica 
vaginalis  propria)  and  a  parietal  layer  (8)  (tunica  vaginalis  reflexa). 
Originally  a  part  of  the  peritoneum,  its  upper  end  becomes  oblit- 
erated, and  the  lower  end  remains  as  a  closed  sac,  the  space  between 
the  layers  being  the  cavity  (10)  of  the  tunica  vaginalis.  It  forms  a 
pouch,  the  digital  fossa  (13),  between  the  epididymis  and  the  testicle. 

Tunica  Albuginea  (12),  the  fibrous  covering, — consists  of  white  fibrous 
tissue,  and  forms  ari  incomplete  vertical  septum  within  the  gland,  the 
corpus  Highmorianum  or  medi- 
astinum testis  (2),  from  which 
fibrous  bands  (trabeculae)  cross 
the  gland,  dividing  its  interior 
into  spaces  for  the  lobules  of 
the  organ. 

Tunica  Vasculosa,  the  vascular 
covering, — lies  beneath  the 
preceding,  and  lines  the  septa 
in  the  interior  of  the  gland. 
It  consists  of  a  plexus  of 
blood-vessels,  held  together  by 
a  delicate  areolar  tissue. 

Structure  of  the  Testis.  The 
glandular  structure  consists  of  250 
to  400  olbules,  which  are  each  con- 
tained in  one  of  the  spaces  formed 
by  the  trabeculae,  and  formed  of  i 
to  3  or  more  minute,  convoluted 

tubes,  the  tubuli  seminiferi.  The  latter  consist  of  a  basement  mem- 
brane, lined  by  several  layers  of  cells,  from  which  the  spermatozoa  are 
developed.  In  the  apices  of  the  lobules  the  tubuli  become  straight,  and 
join  to  form  20  or  30  ducts,  the — 

Vasa  Recta  (4,  Fig.  130), — are  each  about  3^o  mcn  in  diameter;  then 
enter  the  mediastinum,  passing  upward  and  backward,  and  forming 
the— 
Rete  Testis  (5), — a  network  of  anastomosing  tubes  or  channels  in  the 

fibrous  stroma  of  the  mediastinum;  they  end  in  the — 
Vasa  E/erentia  (6), — 12  to  20  ducts,   which  perforate  the  tunica   albu- 
ginea  of  the  testis,  and  form  a  number  of  conical  masses,  the  coni 
vasculosi    which    together    constitute    the   globus    major  (7)  of  the 
Epididymis  (see  Fig.  130). 


APPENDAGES  OF  THE  TESTES  375 

Descent  of  the  Testis.  In  early  foetal  life  the  testes  are  situated  in 
the  abdominal  cavity,  just  below  the  kidneys,  and  are  connected  to  the 
dartos  of  the  scrotum  and  the  tissues  about  the  inguinal  canal  by  a  cord 
named  the  gubtrnaculum  testis,  which  prevents  the  testicle  rising  with  the 
growth  of  the  foetus,  and  the  testicle  is  drawn  first  into  the  inguinal  canal 
and  eventually  into  the  scrotum,  the  cord  itself  becoming  shortened  as 
development  proceeds.  The  descent  begins  about  the  commencement  of 
the  5th  month;  during  the  7th  month  the  testicle  enters  the  inguinal 
canal,  and  ordinarily  arrives  in  the  scrotum  by  the  end  of  the  8th  month. 
A  process  of  peritoneum  is  carried  down  in  front  of  the  testis;  which 
process,  by  obliteration  of  the  canal,  becomes  a  separate  structure,  the 
tunica  vaginalis.  The  structures  of  the  inguinal  canal  are  also  brought 
down  with  the  testicle,  and  constitute  some  of  its  coverings. 

Vessels  and  Nerves.  The  Arteries  are  the  Spermatic,  from  the  aorta 
to  the  testicle  itself;  its  coverings  are  supplied  by  the  superficial  and  deep 
External  Pudic  from  the  femoral,  the  superficial  Perineal  branch  of  the 
Internal  Pudic  from  the  internal  iliac,  and  the  Cremasteric  branch  of  the 
epigastric  from  the  external  iliac. 

Veins. — The  spermatic  veins  emerge  at  the  back  of  the  testis,  receive 
branches  from  the  epididymis,  and  unite  into  the  convoluted  pampini- 
form  plexus,  which  forms  the  chief  mass  of  the  spermatic  cord.  From 
this  plexus  3  or  4  veins  arise,  they  unite  into  2,  and  these  join  into 
a  single  trunk,  which  on  the  right  side  empties  into  the  inferior  vena 
cava,  on  the  left  side  into  the  left  renal  vein. 
Lymphatics, — of  the  testis  terminate  in  the  lumbar  glands;  those  of  its 

coverings  in  the  inguinal  glands. 

Nerves, — of  the  testes  are  derived  from  the  spermatic  plexus,  joined  by 
filaments  from  the  pelvic  plexus;  those  of  their  coverings  are  the  ilio- 
inguinal  branch  of  the  lumbar  plexus,  the  superficial  perineal  branches 
of  the  internal  pudic,  the  inferior  pudendal  branch  of  the  small  sciatic, 
and  the  genital  branch  of  the  genito-crural. 

APPENDAGES  OF  THE  TESTES 

The  Vas  Deferens  (ductus  deferens)  is  the  continuation  of  the 
epididymis,  and  the  excretory  duct  of  the  testicle.  Beginning  at  the 
globus  minor  it  ascends  along  the  back  of  the  spermatic  cord  to  the  in- 
guinal canal,  and  enters  the  abdominal  cavity  through  the  internal  ab- 
dominal ring.  It  curves  around  the  outer  side  of  the  epigastric  artery, 
crosses  the  external  iliac  vessels,  and  descends  into  the  pelvis  at  the  side 
of  the  bladder,  crossing  to  the  inner  side  of  the  ureter  and  the  inner 
border  of  the  vesicula  seminalis.  At  the  base  of  the  prostate  gland  it 


376  HUMAN   ANATOMY 

joins  the  duct  of  the  seminal  vesicle  to  form  the  ejaculatory  duct.  The 
vas  deferens  is  about  2  feet  long,  and  has  a  canal  of  only  half  a  line  in 
diameter.  Its  walls  are  very  dense,  making  it  feel  like  a  piece  of  wire  or 
whip-cord  when  grasped  between  the  fingers.  In  structure  it  consists  of 
three  coats,  the — 

Areolar  Coat, — externally,  beneath  which  is  the — 

Muscular  Coat, — in  2  layers  of  unstriped  fibre,  the  outer  longitudinal, 
and  the  inner  circular;  but  a  third  longitudinal  layer  is  found  at  the 
commencement  of  the  vas,  internal  to  the  circular  layer. 

Mucous  Coat, — internally,  is  pale  and  in  longitudinal  folds;  its  epi- 
thelium is  columnar. 

Artery  of  the  Vas  or  Ductus  Deferens, — a  branch  of  the  superior  vesical, 

ramifies  on  its  coats  and  anastomoses  with  the  spermatic  artery. 
The  Spermatic  Cord  (funiculus  spermaticus)  extends  from  the  internal 
abdominal  ring  to  the  globus  minor  of  the  epididymis,  and  is  about  4 
inches  long.  At  the  external  abdominal  ring  it  rests  upon  the  inguinal 
or  Poupart's  ligament,  having  the  aponeurosis  of  the  external  oblique 
muscle  in  front,  and  the  conjoined  tendon  behind  it.  It  is  composed  of 
arteries,  veins,  lymphatics,  nerves,  and  the  vas  deferens,  bound  together 
by  areolar  tissue,  and  invested  by  the  layers  brought  down  by  the  descent 
of  the  testicle.  The  structures,  composing  the  spermatic  cord,  are  12  in 
number,  and  are  named  as  follows:  the — 

Vas  or  Ductus  Deferens.  Spermatic  Plexus  of  Nerves. 

Spermatic  Artery.  Branch  of  the  Ileo-inguinal  nerve. 

Cremasteric  Artery.  Branch    of   the    Genito-crural    (genito- 

Artery  of  the  Vas  Deferens.          femoral)  Nerve. 

Deferential  Veins.  Obliterated  Processus   Vaginalis  of  the 

Spermatic  Veins.  peritoneum  (ligament  of  Cloquet). 

Internal  Cremaster  Muscle.       Lymphatics. 
Coverings  of  the  Cord,  from  within  outward,  are  the — 

Infundibuliform  Fascia,  from  the  transversalis  fascia. 

Cremasteric  Fascia,  from  the  internal  oblique  muscle. 

Intercolumnar  Fascia,  the  external  spermatic  fascia. 

Superficial  Fascia,  and  the  Skin,  of  the  scrotum. 

The  Vesiculae  Seminales  (d,  Fig.  127)  are  two  lobulated  membranous 
pouches,  which  serve  as  reservoirs  for  the  semen,  and  secrete  a  fluid  to 
be  added  to  the  secretion  of  the  testicles.  They  are  about  2^2  inches  long, 
and  are  situated  externally  to  the  lower  ends  of  the  vasa  or  ductus  defer- 
entia,  between  the  base  of  the  bladder  and  the  rectum.  They  are  com- 
posed of  3  coats, — an  external  areolar,  a  middle  muscular,  and  an  internal 


THE   VULVA  377 

mucous  coat,  lined  with  columnar  epithelium.  Their  anterior  extremities 
converge  toward  the  base  of  the  prostate  gland,  where  a  duct  from  each 
joins  with  the  corresponding  vas  or  ductus  deferens  to  form — 

Ejaculatory  Ducts  (ductus  ejaculatorii), — one  on  each  side,  are  formed 
by  the  junction  of  the  vasa  or  ductus  deferentia  with  the  ducts 
of  the  vesiculae  seminales.  They  are  about  %  inch  in  length,  and 
terminate  in  the  prostatic  portion  of  the  urethra,  by  orifices  on  the 
sides  of  the  verumontanum  (colliculus  seminalis). 

Arteries, — are  derived  from  the  middle  and  inferior  vesical,  and  the 
middle  haemorrhoidal;  they  are  accompanied  by  veins  and  lymphatics. 
Nerves, — are  branches  from  the  pelvic  or  hypogastric  plexus. 

THE  FEMALE  ORGANS  OF  GENERATION 

(Organa  Genital ia  Muliebria) 

THE    VULVA 

The  Vulva,  or  Pudendum  Muliebre,  are  the  external  genital  organs  of  the 
female,  viz., — the  mons  Veneris,  the  labia  majora  and  minora,  the  clitoris, 
and  the  orifice  of  the  vagina.  The — 

Mons  Veneris  (commissura  labiorum  anterior), — is  the  rounded 
eminence  in  front  of  the  pubic  symphysis,  formed  of  fatty  tissue 
beneath  the  skin,  and  covered  with  hair  after  puberty. 

The  Labia  Majora  Pudendi  (i)  are  two  prominent  longitudinal  folds 
extending  from  the  mons  Veneris  to  the  perinaeum.  They  are  formed 
of  hairy  integument  externally  and  modified  skin  internally,  between 
which  are  areolar  and  dartoid  tissues,  fat,  vessels,  nerves,  and  glands. 
They  meet  in  front,  forming  the  anterior  commissure  (10),  and  nearly  meet 
behind  in  the  posterior  commissure  at  the  anterior  boundary  of  the  peri- 
naeum. They  correspond  to  the  scrotum  of  the  male.  The — 

Fourchette  (commissura  labiorum  posterior)  (2), — is  the  curved  anterior 
edge  of  the  perinaeum,  and  between  it  and  the  hymen  (8)  there  is  a 
depression,  the  fossa  navicularis. 

Nerves, — the  superficial  perineal  from  the  pudic,  and  the  inferior 
pudendal  from  the  small  sciatic. 

The  Labia  Minora  Pudendi  (3),  or  Nymphce,  are  two  small  folds,  situated 
internally  to  the  labia  majora,  and  extending  from  the  prepuce  of  the 
clitoris  (praeputium  clitoridis)  (4)  obliquely  backward  for  i%  inches  on 
each  side  ot  the  vaginal  orifice,  where  they  are  lost  on  the  inner  surface 
of  the  labia  majora.  They  are  composed  of  modified  skin,  and  have 


378 


HUMAN   ANATOMY 


FIG.  132. 


sebaceous   follicles    (glandulaa    vestibulares    minores)    on    their   internal 
surface. 

Clitoris, — is  situated  beneath  the  anterior  commissure,  its  glans  (4) 

only  appearing  externally  as  a  small  rounded  tubercle  between  the 

anterior    extremities    of    the    labia 

minora.     It  is  a  diminutive  penis, 

in  all  but  the  corpus  spongiosum 

and  urethra;  having    two  corpora 

cavernosa,     two     crura,    a     glans, 

prepuce,  suspensory  ligament  and    «- 

muscles,    the     erectores     clitoridis 

(ischio-cavernosi) . 
Vestibule  (vestibulum  vaginae)  (6), — 

is  a  triangular  depression  in  front 

of    the    vaginal    orifice,    bounded 

laterally  by  the  labia  minora. 
Meatus  Urinarius  (orificium  urethras 

externum)     (5), — situated    in    the 

vestibule,  about  an  inch  below  the 

clitoris,   and   close   to   the  vaginal 

orifice. 

Bulbi  Vestibuli, — are  two  oblong  erec- 
tile bodies,  situated  one  on  either 

side  of  the  vestibule,  and  consist-   a. 

ing  of  a  venous  plexus  surrounded 

by  a  fibrous  membrane.     They  are 

the  analogues  of  the  bulb  of  the 

corpus  spongiosum  in  the  male. 
Pars  Intermedia, — is  a  small  venous  plexus  situated  between  the  glans 

clitoridis  and  the  bulbi  vestibuli.     It  is  the  analogue  of  the  corpus 

spongiosum. 
Orifice  of  the   Vagina   (7), — is  surrounded  by  the  sphincter  vaginae 

muscle,  and  in  the  virgin  is  sometimes  partly  closed  by  the  hymen. 
^H^men  (8), — a  fold  of  mucous  membrane  situated  across  the  lower  part 

of  the  vaginal  orifice,  of  various  shapes,  usually  a  ring,  but  often 

semilunar,  the  concavity  upward.     It  is  frequently  absent  in  virgins. 

Its  cicatrization  after  rupture   gives   rise  to  small  eminences  along 

the  margin  of  the  vaginal  orifice,  named  the  caruncula  myrtiformes 

(carunculae  hymenales). 
Glands  of  Bartholin  (glandulae  vestibulares  majores), — one  on  each  side 

of  the  vaginal  orifice^  their  ducts  opening  (9)  near  the  inner  sides  of 


THE   VAGINA  379 

the   labia   minora.     They   are    the   analogues   of   Cowper's   glands 
(glandulae  bulbo-urethrales)  in  the  male. 

Nerves, — to  the  labia  minora  as  to  the  labia  majora;  the  bulbi  vestibuli 
and  other  erectile  structures  are  supplied  by  filaments  from  the  dorsal 
nerve  of  the  clitoris,  superficial  perineal,  and  hypogastric  plexus. 

THE  VAGINA 

The  Vagina  is  a  curved  canal  extending  from  the  vulva  to  the  ute     ', 
placed  between  the  bladder  in  front  and  the  rectum  behind.     Its  len 
is  about  2^  inches  along  the  anterior  wall  (paries  anterior),  3^  inc* 
along  the  posterior  wall  (paries  posterior),  and  its  walls  are  usually  in  co 
tact  with  each  other.     It  is  very  dilatable,  especially  near  its  upper  em. 
which  surrounds  the  vaginal  portion  of  the  cervix  uteri,  its  attachment 
extending  higher  up  on  the  posterior  wall  of  the  uterus  than  on  the  anterior 
wall.     Its  relations  are — 

Anteriorly, — the  urethra  and  the  base  of  the  bladder. 
Posteriorly, — the  anterior  wall  of  the  rectum,  and  the  recto-vaginal  fold 
of  peritoneum  which  forms  Douglas'  pouch  (excavatio  recto-uterina) 
behind  its  upper  fourth. 
Laterally, — are  attached  the  levatores  ani  muscles,  and  the  recto-vesical 

portion  of  the  pelvic  fascia. 

Structure  of  the  Vagina.     The  vaginal  wall  consists  of  a  muscular  coat 
(tunica  muscularis)  externally,  a  layer  of  erectile  tissue,  and  a  mucous 
lining  (tunica  mucosa)  covered  with  squamous  epithelium,  and  furnished 
with  mucous  crypts  and  follicles,  but  has  no  glands.     The  vagina  is  par- 
tially covered  laterally  by  the  recto-vesical  portion  of  the  pelvic  fascia. 
Columns  of  the   Vagina  (columnae  rugarum  anterior  et  posterior), — 
are  two  longitudinal  raphes  situated  along  its  inner  surface,  one 
anteriorly,  the  other  posteriorly,  which  are  connected  by  numerous 
transverse  ridges  or  ruga  vaginales. 
Sphincter  Vagina  Muscle, — surrounds  the  lower  end  of  the  vagina;  it  is 

described  on  page  99. 

Vessels  and  Nerves.  The  Arteries  of  the  vagina  are  the  Vaginal 
branches  of  the  internal  iliac,  and  branches  of  the  uterine  artery,  which 
form  in  front  and  behind  a  longitudinal  vessel,  the  azygos  arteries  of  the 
vagina.  The— 

Veins, — are  disposed  similarly  to  the  arteries,  form  a  rich  plexus  in  the 
muscular  and  mucous  coats,  and  terminate  in  the  vaginal  and  uterine 
trunks. 
Lymphatics, — terminate  in  the  pelvic  and  inguinal  glands. 


380  HUMAN   ANATOMY 

Nerves, — are  derived  from  the  hypogastric  plexus,  the  fourth  sacral 
nerve,  and  the  pudic  nerve  (n.  pudendus),  forming  a  vaginal  plexus. 

THE  UTERUS 

The  Uterus  is  a  hollow,  pear-shaped,  muscular  organ,  measuring  about 
3  inches  long,  2  inches  broad,  and  i  inch  thick,  flattened  from  before  back- 
ward, placed  base  upward,  forming  ah  angle  with  the  vagina,  which  par- 
tially receives  its  cervix,  and  situated  in  the  pelvic  cavity,  between  the 
bladder  in  front  and  the  rectum  behind.  Its — 

Fundus  uteri  (A), — is  broad,  convex,  having  walls  %  inch  thick,  and  is 

covered  by  peritoneum. 

Body  (corpus  uteri), — is  about  i%  inches  long,  walls  %  inch  thick,  flat 
anteriorly,  convex  posteriorly,  concave  laterally,  and  joined  to  the 
bladder  by  its  lower  anterior  fourth.  It  is  invested  by  peritoneum 
posteriorly,  and  in  front  for  its  upper  three-fourths. 

FIG.  133. 


Cervix  Uteri  or  Neck, — is  the  lower  constricted  portion,  about  i  %  inches 
long,  walls  Y±  inch  in  thickness,  and  is  embraced  for  %  to  %  inch 
by  the  upper  extremity  of  the  vagina. 

Cavity  of  the  Body  (cavum  uteri)  (B), — is  small  and  triangular,  flattened 
from  before  backward,  about  i%  inches  in  length,  and  has  two  lateral 
cornua  above,  and  a  constricted  orifice,  the  os  internum  (orificium  in- 
ternum  uteri),  at  its  lower  angle,  opening  into  the  cavity  of  the 
cervix. 

Cavity  of  the  Cervix  (canalis  cervicis  uteri), — is  spindle-shaped,  about 
i%  inches  long,  and  presents  on  its  inner  surf  ace  transverse  folds  of 
mucous  membrane  proceeding  from  a  longitudinal  fold,  giving  an 
appearance  named  the  arbor  vitce  (plicae  palmatae)  (o). 

Os  Uteri  (orificium  externum  uteri), — is  a  transverse  orifice  at  the  lower 


THE    UTERUS  381 

end  of  the  cervical  cavity,  opening  into  the  vagina,  and  having  an 
anterior  (labium  anterius)  and  a  posterior  lip  (labium  posterius). 

Ligaments  of  the  Uterus  are  8  in  number, — i  anterior,  i  posterior,  2 
lateral  or  broad  ligaments,  2  sacro-uterine,  and  2  round  ligaments,  all 
except  the  last-named  being  formed  of  peritoneum.  The — 

Anterior  Ligament,  utero-vesical, — is  reflected  from  the  front  of  the 
uterus  on  to  the  bladder.  It  forms  the  floor  of  the  utero-vesical  pouch 
(excavatio  vesico-uterina). 

Posterior  Ligament,  recto-vaginal, — passes  from  the  posterior  wall  of  the 
uterus  over  the  upper  fourth  of  the  vagina,  and  thence  on  to  the 
rectum  and  sacrum,  forming  Douglas'  pouch  (excavatio  recto-uterina) 
behind  the  upper  portion  of  the  vagina. 

Lateral  or  Broad  Ligaments  (ligamenta  lata  uteri)  2, — pass  from  the 
sides  of  the  uterus  to  the  lateral  walls  of  the  pelvis,  and  form  a  septum 
across  the  pelvic  cavity.  They  contain,  between  the  two  folds  of 
peritoneum  of  which  they  are  composed,  the  Fallopian  tubes  (tubae 
uterinas)  the  round  ligaments,  the  ovaries,  the  parovaria  or  organs  of 
Rosenmiiller,  connective  tissue,  unstriped  muscular  fibre,  blood- 
vessels, and  nerves. 

Sacro-uterine  Ligaments  (plicae  recto-uterinae)  2, — pass  from  the  sides 
of  the  uterus  to  the  sides  of  the  rectum,  and  thence  to  the  sacrum. 

Round  Ligaments  (ligamenta  teres  uteri)  2  (G), — are  two  cords,  about  4 
or  5  inches  long,  composed  of  muscular  tissue  prolonged  from  the 
uterus,  also  areolar  and  fibrous  tissue,  vessels  and  nerves,  extending 
one  on  each  side,  from  the  lateral  aspects  of  the  fundus  uteri,  through 
the  inguinal  canals,  to  the  labia  majora,  where  they  are  lost.  Each 
ligament  lies,  for  a  part  of  its  course,  between  the  two  layers  of  the 
broad  ligament,  and  is  covered  by  a  process  of  peritoneum.  The — 

Canal  of  Nuck, — is  the  extension  of  the  above-mentioned  process  of 
peritoneum  into  the  inguinal  canal.  It  exists  in  the  foetus,  but  is 
usually  obliterated  in  the  adult. 

Structure  of  the  Uterus.  The  wall  of  the  uterus  is  composed  of  3 
coats,  an  External  serous,  a  middle  muscular,  and  an  internal  mucous  coat. 
The  muscular  coat  (tunica  muscularis)  forms  the  chief  bulk  of  the  organ, 
and  consists  of  bundles  of  unstriped  muscular  fibres,  disposed  in  3  layers 
interlaced  together;  circular  fibres  predominating  in  the  cervix,  longi- 
tudinal fibres  in  the  body  of  the  uterus.  The — 

Peritoneal  or  Serous  Coat  (tunica  serosa), — invests  the  body  of  the 
organ,  except  its  lower  anterior  fourth. 

Mucous  Coat  (tunica  mucosa), — is  very  thick,  ^(2  to  3^  inch,  and  closely 


382  HUMAN   ANATOMY 

adherent  to  the  muscular  tissue,  having  no  basement  layer  of  con- 
nective tissue.  It  is  covered  with  ciliated  columnar  epithelium,  and 
studded  with  mucous  follicles  and  tubular  glands  (glandulse  uterinae), 
which  are  most  numerous  in  the  cervix. 

Vessels  and  Nerves.  The  Arteries  of  the  uterus  are  the  Uterine  from 
the  internal  iliac,  and  the  Ovarian  from  the  aorta;  the  two  meeting  on  the 
side  of  the  body  and  forming  an  anastomotic  trunk,  from  which  lateral 
branches  are  given  off  to  the  uterus.  They  are  remarkably  tortuous  and 
anastomose  freely.  The — 

Veins, — accompany  the  arteries,  and  in  the  impregnated  state  become 

sinuses.     They  end  in  the  uterine  plexuses. 
Lymphatics, — those  of  the  cervix  end  in  the  pelvic  glands,  those  of  the 

body  in  the  lumbar  glands. 

Nerves, — are  derived  from  the  inferior  hypogastric  and  ovarian  plexuses, 
and  from  the  3d  and  4th  sacral  nerves. 

APPENDAGES  OF  THE  UTERUS 

The  Fallopian  Tubes,  or  Oviducts  (tubas  uterinae)  (D),  are  two  tubes, 

each  about  4  inches  in  length,  and  i  H  6  inch  in  calibre,  situated  in  the  free 

margin  of  the  broad  ligament,  and  extending  from  the  superior  angles  of 

the  uterus  (&)  outward,  to  terminate  in  free,  trumpet-shaped  ends.     They 

open  by  one  end  into  the  uterus  at  its  cornua,  by  the  other  end  into  the 

peritoneal  cavity.     Their  structure  is  similar  to  that  of  the  uterus,  the 

mucous  lining  being  continuous  with  the  uterine  mucous  membrane  and 

with  the  peritoneum,  and  lined  with  ciliated  columnar  epithelium.    Their — 

Isthmus  Tubes  Uterines, — is  the  inner  constricted  third  of  the  tube. 

Ampulla  Tubes  Uterines, — is  the  outer  dilated  portion,  curving  over  the 

ovary. 
Infundibulum  Tubes  Uterince, — the  trumpet-shaped  outer  end,  with  its 

open  mouth,  the  ostium  abdominale  tubce  uterince,  surrounded  by — 
Fimbrice    Tubes    Uterines  (E), — fringe-like  processes,  one  of  which,  the 

fimbria  ovarica,  is  attached  to  the  ovary. 

Hydatids  of  Morgagni  (appendices  vesiculosi)  (see  page  372), — one  or 
more  small  vesicles  floating  on  a  long  stalk  of  peritoneum,  are  fre- 
quently found  in  connection  with  or  near  the  fimbriae. 
Vessels  and  Nerves, — The  vessels  are  those  of  the  ovaries;  the  nerves  are 

branches  from  one  of  the  uterine  nerves. 

The  Ovaries  (ovaria)  (F)  are  two  oval  bodies,  of  grayish-pink  color, 
situated  in  the  broad  ligament,  behind  and  below  the  Fallopian  tubes, 
( tubae  uterinae,)  one  on  each  side  of  the  uterus,  to  which  they  are  attached 


THE    MAMMAE  383 

by  the  ligament  of  the  ovary.  They  each  measure  about  i  %  inches  by  % 
by  H,  and  are  invested  by  peritoneum,  except  posteriorly.  They  are 
composed  of  a  vascular  stroma  containing  the  Graafian  vesicles  (folliculi 
oophori  vesiculosi)  in  various  stages  of  development,  and  are  surrounded 
by  the  tunica  albuginea,  a  condensed  layer  of  the  stroma. 

The  Graafian  Vesicles  (folliculi  oophori  vesiculosi)  are  the  ovisacs 
containing  the  ova,  are  very  numerous  (about  70,000  in  each 
ovary),  vary  in  diameter  from  Hoo  to  %o  inch,  but  after  puberty  a  few 
are  found  of  from  Ho  to  ^  inch  or  more.  Each  vesicle  has  an  external 
fibro-vascular  coat,  and  an  internal  coat  (tunica  externa)  or  ovicapsule, 
(theca  folliculi)  which  is  lined  by  the  membrana  granulosa  (stratum 
granulosum)  and  contains  a  transparent  fluid  of  albuminous  character, 
containing  the  immature  ovum.  The — 

Membrana  Granulosa  (stratum  granulosum), — is  a  layer  of  nucleated 
cells,  lining  the  ovicapsule;  at  one  point  the  cells  are  heaped  up  in  a 
mass,  the  discus  proligerus  (cumulus  oophorus),  in  which  the  ovum 
is  embedded. 

Corpus  Luteum, — is  a  puckered  yellow  spot  in  the  substance  of  the 
ovary,  produced  as  a  result  of  the  rupture  of  a  Graafian  vesicle  and  the 
discharge  of  an  ovum,  probably  by  the  organization  of  the  extrava- 
sated  blood,  forming  lutein  cells.  In  old  age  the  corpus  luteum 
undergoes  involution,  loses  its  yellow  color,  and  is  then  called  the 
corpus  albicans. 

Vessels  and  Nerves.  The  Arteries  are  the  Ovarian,  from  the  aorta, 
which  also  supply  the  Fallopian  tubes,  and  anastomose  with  the  uterine 
arteries.  The — 

Veins, — accompany  the  arteries,  and  form  a  plexus,  the  pampiniform 

plexus,  near  the  ovary. 
Nerves, — are  derived  from  the  inferior  hypogastric  or  pelvic  plexus,  and 

from  the  ovarian  plexus. 

The  Parovarium,  or  Organ  of  Rosenmuller,  is  a  group  of  tubules,  situated 
in  the  broad  ligament,  between  the  ovary  arid  the  Fallopian  tube,  and  con- 
verging to  a  large  duct,  the  duct  of  Gartner,  which  ramifies  in  the  broad 
ligament,  descends  along  the  side  of  the  uterus,  and  terminates  in  a  bulb- 
ous enlargement.  It  is  the  atrophied  remains  of  the  Wolffian  Body  of 
fcetal  life. 

THE  MAMMAE 

The  Mammae,  or  Breasts,  are  two  hemispherical  eminences,  situated  one 
on  each  antero-lateral  aspect  of  the  chest,  extending  from  the  sternum 
to  the  axilla,  and  from  the  3d  rib  to  the  7th.  Each  breast  contains  the 


384 


HUMAN    ANATOMY 


Mammary  Gland  (corpus  mammae)  and  is  surmounted  by  the  nipple 
(papilla  mammae),  around  the  base  of  which  is  a  zone  of  colored  cutaneous 
tissue,  the  areola  mamma,  pink  in  virgins,  darker  in  women  who  have 
borne  children.  In  the  male  the  mammae 

.r  IG«    134" 

are  rudimentary  organs,  but  capable  of 
development  under  special  circumstances. 
Structure  of  the  Mammary  Gland.  Is 
composed  of  15  or  20  lobes  (lobi  mammae) 
and  their  ducts  (i),  with  a  packing  of 
areolar  and  adipose  tissue  (subcutaneous 
tela),  enveloped  by  a  thin  fibrous  capsule 
or  stroma  which  forms  septa  between  the 
lobes.  Each  lobe  is  made  up  of  lobules 
(2),  and  these  again  are  formed  by  the 
aggregation  of  alveoli,  terminal  vesicles 
by  which  the  milk  is  secreted.  The — 
Tubuli  Lactiferi  (ductus  lactiferi)  (i), 

— are    the    excretory    ducts    of   the 

lobes,  one  for  each.    They  are  formed 

by  the  junction  of  the  ducts  from 

each  lobule,   and  converge  towards 

the  areola,  beneath  which  they  form 

ampulla  or  dilatations,  and  thence, 

piercing  the  nipple,  open  on  its  summit  by  separate  orifices. 
Vessels  and  Nerves.     The  Arteries  are  derived  from  the   thoracic 
branches  of  the  axillary,  the  intercostals,  and  the  internal  mammary 
arteries. 

Veins, — form  the  circulus  venosus,  an  anastomotic  venous  circle  around 

the  base  of  the  nipple,  from  which  larger  veins  run  outward,  and  ter- 
minate in  the  axillary  and  internal  mammary  veins. 
Lymphatics, — terminate  in  the  axillary  glands;   a  few  going  to  the 

anterior  mediastinal  glands. 
Nerves, — are  derived  from  the  lateral  cutaneous  branches  of  the  4th, 

5th,  and  6th  intercostal  nerves  and  from  the  thoracic  portion  of  the 

sympathetic  cord. 

HERNIA 

A  Hernia  is  a  protrusion  of  any  viscus  from  its  natural  cavity.  The 
term,  when  unqualified  as  to  the  viscus,  is  understood  to  mean  a  protrusion 
of  the  intestines  or  mesentery,  or  both,  from  the  abdominal  cavity.  Ana- 
tomically the  most  important  hernias  are — 


INGUINAL   HERNIA  385 

Oblique  Inguinal  Hernia, — in  which  the  protrusion  follows  the  spermatic 
cord  through  the  inguinal  canal;  passing  to  the  outer  side  of  the  epi- 
gastric artery,  and  through  both  the  internal  and  external  abdominal 
rings. 

Direct  Inguinal  Hernia, — occurs  at  Hesselbach's  triangle,  escaping  to 
the  inner  side  of  the  epigastric  artery,  and  through  the  subcutaneous 
inguinal  or  external  abdominal  ring  only. 

Femoral  Hernia, — in  which  the  protrusion  descends  through  the  femoral 
or  crural  canal. 

H  INGUINAL  HERNIA 

The  Inguinal  Canal  is  a  passage  in  the  abdominal  wall,  parallel  to  the 
inguinal  or  Poupart's  ligament,  and  just  above  it.  It  commences  at  the 
abdominal  inguinal  or  internal  abdominal  ring  and  ends  at  the  subcu- 
taneous inguinal  or  external  abdominal  ring  (i),  being  about  i^  inches  in 
length.  It  serves  for  the  passage  of  the  spermatic  cord  in  the  male,  and 
the  round  ligament  of  the  uterus  in  the  female;  is  directed  downward  and 
inward,  and  is  bounded  as  follows: — 

Anteriorly, — the  skin,    superficial  fascia,   (camper's)    external  oblique 
muscle  for  its   entire   length,    and    the  internal  oblique  (the  part 
attached  to  the  inguinal  ligament)  for  the  outer  third  of  the  canal. 
Posteriorly, — the  conjoined  tendon  of  the  internal  oblique  and  trans- 
versalis, transversalis    fascia,   triangular  fascia   (5)   for  the  medial 
two-thirds,  sub-peritoneal  tissue,  transversalis  fascia,  and  peritoneum 
for  its  entire  length. 
Above, — the  arched  fibres  of  the  internal  oblique  and   transversalis 

muscles. 

Below, — the  union  of  the  transversalis  fascia  (5)  with  Poupart's  (in- 
guinal) ligament  (10). 

The  Internal  or  Deep  Abdominal  Ring  (annulus  inguinalis  abdo minis), — 
is  an  oval  opening  in  the  transversalis  fascia,  formed  by  the  prolongation 
of  this  fascia  around  the  cord,  as  the  infundibuliform  fascia.  It  lies  Y2 
inch  above  Poupart's  (inguinal)  ligament  (10)  and  midway  between  the 
anterior  superior  spine  of  the  ilium  and  the  spine  of  the  pubes  (8).  It  is 
bounded  above  and  externally  by  the  arched  fibres  of  the  transversalis 
muscle;  below  and  internally  by  the  epigastric  vessels.  The — 

Deep  Epigastric  Artery, — lies  between  the  transversalis  fascia  and  the 
peritoneum,  passing  obliquely  upward  and  inward  along  the  lower  and 
inner  margins  of  the  internal  ring. 

Infundibuliform  Fascia, — or  infundibuliform  process  of  the  transversalis 
fascia,  is  a  thin,  funnel-shaped  membrane,  arises  from  the  circum- 
25 


386 


HUMAN   ANATOMY 


ference  of  the  internal  ring,  and  is  continued  (internal  spermatic 
fascia)  around  the  cord  and  testis,  enclosing  them  in  a  distinct 
pouch. 

The  External  or  Superficial  Abdominal  Ring  (annulus  inguinalis  sub- 
cutaneous) (i), — is  a  somewhat  triangular  opening  in  the  aponeurosis  of 
the  external  oblique  muscle,  situated  just  above  and  external  to  the  crest 
of  the  pubes.  It  is  about  i  inch  long,  and  ^  inch  wide,  and  is  bounded 
laterally  by  its  own  margins,  called  the  external  (crus  inferius)  (2)  and 
internal  (crus  superius)  (3)  pillars  of  the  ring.  It  may  be  easily  felt  in 


10 


the  living  male,  by  invaginating  the  skin  of  the  scrotum  with  the  finger, 
and  feeling  up  along  the  spermatic  cord  (9).  It  is  much  larger  in  men 
than  in  women.  The — 

Inter  columnar  or  External  Spermatic  Fascia  (fibrae  intercrurales)  (6), — 
is  formed  by  tendinous  fibres  which  arch  across  the  lower  part  of  the 
aponeurosis  of  the  external  oblique,  between  the  pillars  of  the  ex- 
ternal ring,  and  are  connected  together  by  delicate  fibrous  tissue. 
It  is  continued  downward  as  a  tubular  prolongation  around  the  cord 
and  testis,  enclosing  them  in  a  distinct  sheath. 

Cremasteric  Fascia  (fascia  cremasterica), — passes  through  the  external 
ring,  and  consists  of  a  series  of  muscular  loops,  united  by  areolar 
tissue,  forming  a  thin  covering  over  the  spermatic  cord  and  testis. 


INGUINAL   HERNIA 


38? 


The  muscular  fibres  (Cremaster  muscle)  are  supposed  to  have  been 
originally  part  of  the  internal  oblique  muscle,  carried  down  by  the 
testicle  in  its  descent  to  the  scrotum.  It  does  not  exist  in  the 
female. 


FIG.  136. 


Poupart's  Ligament  (ligamentum  inguinale),  or  the  Crural  Arch,  is 
that  portion  of  the  aponeurosis  of  the  external  oblique  muscle  which 

extends  from  the  anterior  supe- 
rior spine  of  the  ilium  to  the 
spine  of  the  pubes.  Its  lower 
portion  (3)  forms  the  external 
pillar  of  the  external  abdominal 
ring,  and  its  reflection  along  the 
pectineal  line  is  called  Gimbernafs 
ligament  (ligamentum  lacunare) 
(2).  Other  fibres,  reflected  be- 
hind the  internal  pillar  of  the 
ring  (4),  upward  to  the  linea 
alba,  are  termed  the  triangular 
fascia  (ligamentum  inguinale  re- 
flexum)  (i). 

Gimbernat's  Ligament  (liga- 
mentum lacunare)  (2), — is 
that  portion  of  the  aponeu- 
rosis of  the  external  oblique 
which  is  reflected  upward 
and  outward  from  the  spine 
of  the  os  pubis  to  be  inserted 
into  the  pectineal  line.  Its> 
anterior  margin  is  continuous  with  Poupart's  (inguinal)  ligament. 
Triangular  Fascia  (ligamentum  inguinale  reflexum)  (i),— is  a  tri- 
angular band,  attached  by  its  apex  to  the  pectineal  line,  where  it  ia 
continuous  with  Gimbernat's  (lacunar)  ligament;  passes  inward 
beneath  the  spermatic  cord,  behind  the  internal  pillar  (crus  superius) 
of  the  external  or  subcutaneous  inguinal  ring,  and  in  front  of  the 
conjoined  tendon,  to  interlace  with  its  fellow  of  the  opposite  side  at 
the  linea  alba  (see  5,  Fig.  134).  It  is  often  undeveloped  or  wanting. 

Hesselbach's  Triangle  is  a  small  triangular  space  on  the  lower  ab- 
dominal wall,  bounded  externally  by  the  deep  epigastric  artery,  internally 
by  the  margin  of  the  rectus  muscle,  below  by  Poupart's  (inguinal)  liga- 


388  HUMAN    ANATOMY 

ment.     Its  inner  ^  is  crossed  by  the  conjoined  tendon.     Through  this 
space  a  direct  inguinal  hernia  forces  its  way.     The — 

Inguinal  Peritoneal  Fossce, — are  3  depressions  of  peritoneum  in  the  in- 
guinal region  above  Poupart's  (inguinal)  ligament.  The  internal 
(fovea  supravesicalis)  and  middle  (fovea  inguinalis  medialis)  ones  lie 
in  Hesselbach's  triangle,  the  external  fossa  (fovea  inguinalis  lateralis) 
usually  corresponds  to  the  internal  abdominal  or  abdominal  inguinal 
ring. 

Coverings  of  Inguinal  Hernia  depend,  in  the  oblique  form,  upon  the 
extent  to  which  the  hernia  descends  in  or  through  the  inguinal  canal. 
When  it  has  escaped  from  the  external  abdominal  or  subcutaneous  in- 
guinal ring,  and  is  therefore  complete,  its  coverings,  from  without  inward, 
are  7  in  number,  as  follows: — 

1.  Skin. 

2.  Superficial  Fascia, — 2  layers. 

3.  Inter  columnar  Fascia, — from  the  external  abdominal  ring. 

4.  Cremasteric  Fascia, — from  the  inguinal  canal. 

5.  Infundibuliform  Fascia, — from  the  internal  abdominal  ring. 

6.  Subserous  Areolar  Tissue, — almost  inappreciable. 

7.  Peritoneum, — the  hernial  sac  proper. 

Direct  Inguinal  Hernia  has  the  same  coverings,  except  that  the  Conjoined 
Tendon  is  substituted  for  the  cremasteric  fascia,  and  the  Transversalis 
Fascia  for  the  infundibuliform. 

FEMORAL  HERNIA 

The  Femoral  or  Crural  Canal  is  a  narrow  interval,  %  to  %  inch  long, 

between  the  femoral  vein  (4)  and  the  inner  wall  of  the  femoral  sheath 

(fascia  cruris),   extending  from   Gimbernat's   (lacunar)   ligament  to  the 

saphenous  opening  (fossa  ovalis).     It  exists  as  a  distinct  canal  only  when 

the  sheath  has  been  separated  from  the  vein  by  the  pressure  of  a  hernia 

or  tumor,  or  by  dissection.     It  lies  beneath  Poupart's  (inguinal)  ligament 

(i),  is  closed  above  by  the  septum  crurale  of  Cloquet  (septum  femorale), 

below  by  the  cribriform  fascia  (fascia  cribrosa),  and  is  bounded  as  follows: — 

Anteriorly, — by  a  continuation  downward,  under  Poupart's  (inguinal) 

ligament,  of  the  transversalis  fascia,  covered  by  the  falciform  process 

(margo  falciformis)  of  the  fascia  lata. 

Posteriorly, — by  a  downward  continuation  of  the  iliac  fascia,  covering 

the  pubic  portion  of  the  fascia  lata. 

Externally, — by  the  fibrous  septum  separating  it  from  the  inner  side  of 
the  femoral  vein. 


FEMORAL   HERNIA 


389 


FIG.   137. 


Internally, — by  the  outer  edge  of  Gimbernat's  (lacunar)  ligament,  and 
the  junction  of  the  processes  of  the  transversalis  fascia  and  the  iliac 
fascia,  which  form  the  inner  side  of  the  femoral  sheath. 

The  Femoral  or  Crural  Ring  (annul us  femoralis),  the  upper  opening  of 
the  femoral  canal,  is  an  oval-shaped  opening,  about  ^  inch  in  diameter 

(larger  in  the  female),  situated 
below  the  internal  abdominal  or 
subcutaneous  inguinal  ring  (7)  and 
Poupart's  (inguinal)  ligament  (i), 
and  between  the  inner  side  of  the 
femoral  vein  and  the  margin  of 
Gimbernat's  (lacunar)  ligament 
(5).  It  is  closed  by  the  septum 
crurale  (septum  femorale)  and  a 
small  lymphatic  gland.  The  arrow 
in  the  figure  points  into  the  fem- 
oral ring.  The — 
Femoral  Vein  (4), — lies  next  on 

its  outer  side. 

Deep  Epigastric  Artery  (a.  epi- 
gastrica  inferior), — crosses  its 
upper  and  outer  angle. 

Obturator  Artery, — when  arising  from  a  common  trunk  with  the  epi- 
gastric, as  it  does  once  in  3^  subjects,  may  lie  close  along  its  internal 
and  superior  margins. 
Communicating  Branch, — between   the  deep  epigastric  and  obturator 

arteries,  lies  in  front  of  the  ring. 
Spermatic  Cord  (funiculus  spermaticus), — in  the  male,  lies  directly  above 

its  anterior  margin,  replaced  by  the  round  ligament  in  the  female. 
Septum  Crurale,  or  Fascia  of  Cloquet  (septum  femorale), — is  a  layer  of 
condensed  areolar  tissue,  supporting  a  lymphatic  gland,  and  per- 
forated for  the  passage  of  lymphatic  vessels.     It  lies  across  the  femoral 
ring,  and  forms  one  of  the  coverings  to  any  hernia  escaping  thereby. 

The  Saphenous  Opening  (fossa  ovalis),  the  lower  orifice  of  the  femoral 
canal,  is  an  oval-shaped  aperture,  i^  by  ^  inch  in  diameter,  formed  by  a 
reflection  of  the  fascia  lata  inward,  around  and  under  the  end  of  the  in- 
ternal saphenous  vein  (3).  It  is  situated  below  the  inner  third  of  Pou- 
part's (inguinal)  ligament,  and  is  covered  by  the  cribriform  fascia  (fascia 
cribrosa).  Its  inner  margin  curves  upward  behind  the  saphenous  vein 
and  under  the  outer  margin,  and  is  blended  with  the  pubic  portion  of  the 


HUMAN   ANATOMY 

fascia  lata  over  the  pectineus  muscle.     Its  outer  margin  curves  over  the 

inner  to  the  spine  of  the  pubes,  as  a — 

Falciform  Process,  or  Superior  Cornu  (margo  falciformis), — is  thin  but 
strong,  sharply  defined,  and  lies  on  a  plane  anterior  to  the  inner 
margin.  It  ascends  in  front  of  the  femoral  vessels,  and  curving 
inward  is  attached  toPoupart's  (inguinal)  ligament,  the  spine  of  theos 
pubis,  and  the  pectineal  line,  where  it  is  continuous  with  the  pubic 
portion.  It  is  sometimes  named  the  ligament  of  Burns,  its  pubic  end 
is  called  the  ligament  of  Hey. 

Cribriform  Fascia  (fascia  cribrosa)  (n,  Fig.  134), — is  the  portion  of  the 
deep  layer  (Scarpa's)  of  the  superficial  fascia  which  covers  the 
saphenous  opening  (fossa  ovalis).  It  is  perforated  by  the  internal 
saphenous  vein  and  by  numerous  blood-vessels  and  lymphatics. 

The  Femoral  or  Crural  Sheath,  the  investing  sheath  of  the  femoral  ves- 
sels, is  a  funnel-shaped  prolongation  of  the  lining  fasciae  of  the  abdomen, 
the  transversalis  fascia  in  front,  and  the  iliac  fascia  behind.  The  sheath 
is  divided  by  two  septa  into  3  compartments,  the  external  of  which 
contains  the  femoral  artery,  the  middle  one  the  femoral  vein,  the  internal 
one  being  the  femoral  canal.  The  sheath  is  perforated  anteriorly  by  the 
genito-crural  nerve,  internally  by  the  internal  saphenous  vein,  and  forms 
one  of  the  coverings  of  a  femoral  hernia.  The — 

Deep  Crural  Arch, — is  the  thickened  border  of  the  transversalis  fascia, 

which  arches  across  the  front  of  the  crural  sheath,  and  is  intimately 

connected  to  it.     Externally  it  is  attached  to  the  centre  of  Poupart's 

(inguinal)  ligament,  internally  it  is  inserted  into  the  pectineal  line 

/behind  the  conjoined  tendon. 

Coverings  of  Femoral  Hernia  depend  upon  whether  the  hernia  has  or 
has  not  escaped  from  the  saphenous  opening  (fossa  ovalis) ,  and  is  therefore 
complete  or  incomplete.  In  the  latter  case,  the  covering,  from  without 
inward  would  be — skin,  superficial  fascia,  cribriform  fascia,  femoral 
sheath,  septum  crurale,  subserous  areolar  tissue  (fascia  propria  of  Sir 
Astley  Cooper),  and  peritoneum.  The  coverings  of  a  complete  femoral 
. Jifitnia.  axe.  as  follows: — 

i.  Skin. 
I      2.  Superficial  Fascia, — its  superficial  layer  (subcutaneous  tela). 

3.  Cribriform  Fascia, — from  the  saphenous  opening. 

4.  Femoral  Sheath, — from  the  transversalis  fascia. 

5.  Septum  Crurale, — from  the  femoral  ring. 

6.  Subserous  Areolar  Tissue, — the  fascia  propria  of  Cooper. 

7.  Peritoneum, — the  proper  hernial  sac. 


THE   PELVIC   CAVITY  39 1 

THE  PERINEUM,  PROPER 

The  Perinaeum  is  a  triangular  space  containing  the  structures  which 
close  the  inferior  outlet  of  the  pelvic  cavity  anterior  to  a  line  drawn  be- 
tween the  tuberosities  of  the  ischia.  Posteriorly  to  thisline  the  correspond- 
ing space  is  named  the  I schio-rectal  Region.  The  Perinaeum  is  bounded 
laterally  by  the  rami  of  the  pubes  and  ischia,  anteriorly  by  the  symphysis 
pubis,  and  posteriorly  by  the  line  above  mentioned,  which  averages  about 
2%  inches  in  length. 

For  the  Muscles  of  the  Perinaeum,  see  page  98. 

THE  PELVIC  CAVITY 

The  Pelvic  Cavity  is  that  portion  of  the  abdominal  cavity  which  lies 
below  the  level  of  the  ilio-pectineal  line  and  the  promontory  of  the  sacrum. 
The  osseous  pelvis  is  described  on  page  9.  The  boundaries  of  the  pelvic 
cavity  are  as  follows: — • 

Anteriorly  and  Laterally, — the  pubes  and  ischia,  covered  by  the  obturator 

muscles. 
Posteriorly, — the  sacrum  and  coccyx,  the  pyriformis  muscles,  and  the 

great  sacro-sciatic  ligaments  (lig.  sacro-tuberosa). 
Floor, — is  formed  by  the  recto-vesical  fascia,  covering  the  levator  ani 
and  coccygeus   muscles  of  each  side,  and  the  triangular  ligament 
(diaphragma-urogenitale)  of  the  urethra. 

Contents  of  the  Pelvic  Cavity  are  the  bladder,  rectum,  some  convolu- 
tions of  the  small  intestine,  and  some  of  the  organs  of  generation.  They 
are  partially  covered  by  peritoneum,  and  supplied  with  vessels  and  nerves. 

THE  PELVIC  FASCIA 

The  Pelvic  Fascia  lines  the  pelvic  cavity  and  is  continuous  with  the 

iliac  and  transversalis  fascia  above.     At  the  level  of  a  line  drawn  from  the 

back  of  the  symphysis  pubis  to  the  spine  of  the  ischium,  it  is  thickened  into 

a  white  line  or  band  (arcus  tendineus),  where  it  gives  origin  to  the  levator 

ani  muscle,  and  divides  into  2  layers,  the  recto-vesical  fascia  or  visceral 

layer,  and  the  obturator  fascia  or  parietal  layer.     The — 

Recto-vesical  Fascia,  visceral  layer  of  the  pelvic  fascia, — descends  from 

the  white  line  (arcus  tendineus)  over  the  upper  or  pelvic  surface  of 

the  levator  ani  muscle,  and  is  prolonged  over  the  prostate  gland, 

rectum,  vesiculae  seminales,  and  the  bladder,  forming  the  lateral  true 

ligaments  of  the  latter  organ. 

Obturator  Fascia,  the  parietal  layer  of  the  pelvic  fascia, — descends  from 
the  white  line  along  the  wall  of  the  pelvis,  and  covers  the  obturator 


392 


HUMAN    ANATOMY 


interims  muscle,  near  the  lower  border  of  which  it  forms  a  canal  be- 
tween its  layers,  Alcock's  canal)  for  the  pudic  vessels  and  nerve. 
Above  this  canal  it  gives  off  a  thin  membrane,  the  ischio-rectal  or  anal 
fascia  over  the  lower  or  perineal  surface  of  the  levator  ani  muscle;  also 
a  process,  which  with  its  fellow  of  the  opposite  side  forms  the  deep 
(superior)  layer  of  the  triangular  ligament  (diaphragma  urogenitale). 
Illustration  of  the  Pelvic  Fascia.     The  capital  letter  K,  having  a  hori- 
zontal arm  added  to  it,  thus  K™,  will  illustrate  the  pelvic  fascia  of  the  right 
side,  seen  from  the  front  in  vertical  section.     The  vertical  line  of  the  K 
represents  the  pelvic  fascia  above,  the  obturator  fascia  below.     The  upper 
arm  represents  the  lateral  ligament  of  the  bladder,  the  horizontal  arm  the 
recto-vesical  fascia,  and  the  lower  arm  the  ischio-rectal  fascia.     The  space 
between  the  lower  arm  and  the  vertical  line  represents  the  ischio-rectal 
fossa. 

THE  MALE  PERINEUM 

The  Male  Perinaeum,  in  the  adult,  varies  in  breadth  on  the  base  line, 
from  2  to  3^  inches,  the  average  FIG.  138. 

being  2%  inches.  Its  middle  line 
is  convex,  corresponds  to  the  bulb 
of  the  urethra,  and  presents  a 
prominent  raphe,  which  is  con- 
tinuous in  front  with  the  raphe 
of  the  scrotum.  Its  muscles  are 
described  on  page  98. 

Fasciae  of  the  Perinaeum  are 
superficial  and  deep,  each  con- 
sisting of  two  layers;  the  deep 
fascia  being  usually  called  the 
triangular  ligament  of  the  urethra. 
The— 

Superficial  Layer  of  the  Super- 
ficial Fascia  (subcutaneous 
tela), — is  thick,  loaded  with 
fat,  and  continuous  with  the 
subcutaneous  fascia  of  the 
thighs. 

Deep  Layer  of  the  Superficial  Fascia,  Colics'  Fascia, — is  thin  but  strong, 
continuous  in  front  with  the  dartos  of  the  scrotum,  and  attached  on 
each  side  to  the  rami  of  the  pubes  and  ischium;  posteriorly  it  joins  the 
deep  perimeal  fascia  under  the  superficial  transversus  perinaei  muscle. 


THE   MALE   PERINEUM  393 

Superficial  Layer  of  the  Deep  Perinaal  Fascia  (fascia  diaphragmatis 
urogenitalis  inferior), — is  triangular  in  shape,  and  extends  from  the 
sides  of  the  pubic  arch  and  the  sub-pubic  ligament,  laterally  to  the 
rami  of  the  pubes  and  ischia,  and  posteriorly  to  the  central  tend- 
inous portion  of  the  perinaeum,  where  it  becomes  blended  with 
Colic's  fascia  and  the  deep  layer  of  the  deep  fascia.  It  embraces 
the  anterior  part  of  the  membranous  portion  of  the  urethra. 
Deep  Layer  of  the  Deep  Perinceal  Fascia  (fascia  diaphragmatis  urogenitalis 
superior), — has  the  same  attachments  as  the  superficial  layer  above 
described,  in  its  course  it  embraces  the  posterior  part  of  the  mem- 
branous portion  of  the  urethra,  and  is  in  connection  with  the  apex 
of  the  prostate  gland. 

Buck's  Fascia  is  a  continuation  of  the  deep  layer  of  the  superficial  fascia 
of  the  perinaeum,  extending  forward  upon  the  penis,  which  itinvests  com- 
pletely as  far  as  the  glans.     It  is  continuous  above  with  the  suspensory 
ligament  of  the  penis,  and  is  held  by  some  anatomists  to  prove  that  the 
deep  layer  aforesaid  is  not  continuous  in  front  with  the  dartos  of  the 
scrotum.     This  fascia  was  named  from  Dr.  Buck,  an  American  surgeon, 
who,  in  1846,  first  insisted  on  the  importance  of  this  structure.     It  modifies 
the  direction  of  urinary  infiltration  of  the  perinaeum,  until  perforated. 
The  Superficial  Perin&al  Interspace  or  Fossa  is  the  interval  between  the 
deep  layer  of  the  superficial  fascia  (Colles'  fascia)  and  the  triangular 
ligament    or    urogenital    diaphragm.     It    contains    the    following 
structures: — 

Crura  of  the  Penis  (4).  1 '  schio-cavernosus  or  Erector  Penis 

Corpus  Spongiosum  (corpus  Muscle  (10). 

cavernosum  urethrae).  Superficial    Transversus    Pcrincei 

Bulb  of  the  Urethra.  Muscle  (14). 

Bulbo-cavernosus  or  Accelerator        Superficial    Transversus    Perinai 
Urines  Muscle  (8).  Artery. 

Superficial  Perinaal  Vessels   and 

Nerves  (5). 

The  Deep  Perinceal  Interspace  or  Fossa  is  the  interval  between  the  two 
layers  of  the  triangular  ligament  or  urogenital  diaphragm.  It 
contains  the  following  structures: — 

Membranous  Urethra.  Dorsal  Vein  of  the  Penis. 

Deep  Transversus  Perinai  or  Com-         Artery  of  the  Bulb, 
pressor  Urethrce  Muscle.  Nerve  of  the  Bulb. 

Pudic  Vessels  and  Nerve  (n).  Plexus  of  Veins. 

Cowper's  Glands  (glandula  bulbo- 
yrethrales)  and  Ducts. 


394 


HUMAN    ANATOMY 


Central  Tendinous  Point  is  a  fibrous  point  in  the  middle  line  of  the 
perinaeum,  internal  to  the  deep  layer  of  the  superficial  fascia  and  about  % 
inch  in  front  of  the  anus.  It  corresponds  to  the  centre  of  the  posterior 
margin  or  base  of  the  triangular  ligament  or  urogenital  diaphragm  (12), 
and  is  the  point  of  attachment  for  4  converging  muscles,  the —  external 
sphincter  (16),  bulbo-cavernosus  or  accelerator  urinae  (8),  and  two  super- 
ficial transverse  perinaeal  (14). 

ISCHIO-RECTAL   REGION 

The  Ischio-rectal  Space  is  the  horse-shoe-shaped  space  behind  and  above 
the  perinaeum.  It  is  somewhat  triangular  in  cross-section.  It  extends 
posteriorly  to  the  tip  of  the  coccyx,  laterally  to  the  tuberosities  and  rami 
of  the  ischia  and  anteriorly,  on  each  side,  it  presents  an  Anterior  Exten- 
sion which  extends  forwards  as  far  as  the  body  of  the  pubis.  In  fat  sub- 
jects this  extension  is  distended  with  fat,  in  which  case  it  is  triangular 

FIG.  139. 


in  cross -section,  the  floor  being  formed  by  the  deep  layer  of  the  trian- 
gular ligament  (uro-genital  diaphragm),  outer  wall  by  obturator  fascia 
and  muscle,  and  the  inner  wall  by  the  leva  tor  an  i  muscle  and  its  fascia. 
In  the  middle  line  it  presents  the  anal  orifice,  and  deeply  on  each  side, 
the  Ischio-rectal  Fossa,  which  contains  the  lower  part  of  the  rectum,  areolar 
tissue  and  fat.  The  fossa  is  about  i  inch  broad  at  its  base  and  about  2 


THE    FEMALE   PERINEUM  395 

inches  deep;  its  apex,  directed  upward,  corresponds  to  the  junction  of  the 
obturator  fascia  and  the  ischio-rectal  fascia.  It  contains  the — • 

Superficial  Fascia  (subcutaneous  tela), — is  thick,  areolar  in  texture, 
with  much  fat  in  its  meshes,  also  branches  of  the  perforating  cu- 
taneous nerve.  It  is  a  single  layer. 

Muscles, — the  corrugator  cutis  ani,  external  and  internal  sphincters  (16), 
and  the  levator  ani  (18). 

Rectum, — surrounded  by  areolar  tissue  and  fat. 

Internal  Pudic  (pudenda!)  Artery  (n), — with  its  veins  and  the  two 
divisions  of  the  nerve,  about  ^  inch  above  the  margin  of  the  tuber- 
osity  of  the  ischium. 

Inferior  Hemorrhoidal  Vessels  and  Nerves  (13), — cross  the  space  trans- 
versely. 

Superficial  Perinceal  Vessels  (5)  and  Nerves  (3), — in  the  front  part  of  the 
space  for  a  short  distance. 

Branch  of  the  ^th  Sacral  Nerve, — at  the  back  of  the  space,  near  the  coccyx. 

Ischio-rectal  or  Anal  Fascia, — a  thin  membrane  given  off  from  the  obtu- 
rator fascia  over  the  levator  ani  muscle,  at  the  apex  of  the  fossa  (see 
pages  390-391). 

Obturator  Fascia, — covering  the  obturator  internus  muscle,  at  the  outer 
side  of  the  fossa  (see  page  390). 

Recto-vesical  Fascia, — invests  the  internal  surface  of  the  levator  ani 
muscle,  near  the  base  of  the  fossa;  also  the  rectum  at  the  inner  side 
of  the  fossa  (see  page  390). 

THE  FEMALE  PERINEUM 

The  Female  Perinaeum  performs  the  special  function  of  supporting  the 
posterior  wall  of  the  vagina,  and  thereby  aiding  materially  in  the  support 
of  the  whole  vagina,  the  uterus  and  the  bladder.  The — 

PerincBal  Body, — is  the  pyramidal-shaped  prolongation  of  the  female 
perinaeum  upward  between  the  vagina  and  the  rectum.  It  measures 
about  \Y±  inches  antero-posteriorly,  and  extends  laterally  from  one 
ischial  tuberosity  to  the  other.  In  it  are  situated  the  muscles  of  the 
external  organs  of  generation. 

Differences  between  the  Female  and  Male  Perinsea  are  chiefly  due 
to  the  perforation  of  the  structures  in  the  median  line  of  the  female 
perinaeum  by  the  vulvo-vaginal  passage.  The — 

Superficial  Fascia, — is  incomplete,  by  reason  of  its  perforation  by  the 
orifice  of  the  vulva,  but  consists  of  two  layers,  subcutaneous  tela  and 
Colics'  fascia,  as  in  the  male. 


396  HUMAN    ANATOMY 

Deep  Perinaal  Fascia  (urogenital  diaphragm), — being  also  perforated 
by  the  vagina  is  less  apparent  than  in  the  male,  though  presenting 
two  layers,  with  the  urethra  perforating  them,  as  in  the  other  sex. 

Bulbi  Vestibuli  and  Paries  Intermediates, — represent  the  corpus  spongio- 
sum  of  the  male,  divided  into  two  lateral  segments. 

Prostate  Gland, — is  absent  in  the  female,  but  its  place  is  occupied  by  a 
number  of  minute  glands  disposed  around  the  neck  of  the  bladder. 

Muscles, — The  Sphincter  Vaginae  in  the  female,  takes  the  place  of  the 
bulbo-cavernosus  or  accelerator  urinse  in  the  male;  the  Superficial 
Transversus  Perinaei  is  similar  in  both  sexes;  the  Erector  Clitoridis 
is  smaller  than  the  erector  penis,  but  differs  in  no  other  respect; 
both  are  called  ischio-cavernosus;  the  Deep  Transversi  Perinaei 
or  Compressores  Urethras  are  separate  and  attenuated  in  the 
female,  their  anterior  fibres  passing  in  front  of  the  urethra,  the 
middle  fibres  to  the  sides  of  the  vagina,  the  posterior  fibres  to 
the  central  tendinous  point  of  the  perinaeum. 

Structures  Divided  in  Lithotomy.  In  the  Lateral  Operation  the 
knife  is  inserted  deeply  i^  inches  in  front  of  the  anus,  a  little  to  the  left 
of  the  median  line,  and  the  incision  is  carried  obliquely  backward  and 
outward,  becoming  more  superficial  as  it  is  extended,  to  a  point  midway 
between  the  anus  and  the  tuberosity  of  the  left  ischium,  dividing  the — 

Skin  and  Superficial  Fascia  (first  layer  of  the  latter). 

Inferior  Hemorrhoidal  Vessels  and  Nerves  (13). 

Deep  Layer  of  the  Superficial  Fascia  (6). 

Superficial  Perinaal  Vessels  (5)  and  Nerves  (3). 

Bulbo-cavernosus   (Accelerator  Urinae)  Muscle  (8)  (posterior  fibres). 

Superficial  Transversus  Ferincei  Muscle  (14)  and  Artery. 

Inferior  Layer  of  the  Triangular  Ligament  (12). 

Deep  Transversus  Perin&al  (Compressor  Urelhrce)  Muscle  (a  few  fibres). 

Levator  Ani  Muscle  (18)  (anterior  fibres). 

Membranous  and  Prostatic  Portions  of  the  Urethra  (2). 

Superior  Layer  of  the  Triangular  Ligament  (Urogenital  diaphragm)  (12). 

Prostate  Gland  (part  of  the  left  lobe). 

Neck  of  the  Bladder  (in  part). 
In  Median  Lithotomy,  the  incision,  i}-^  inches  long,  is  made  transversely 

through  the  central  tendinous  point  and  raphe,  dividing  the — 
Skin  and  Superficial  Fascia. 

Sphincter  Ani  Muscle  (16)  (some  of  its  anterior  fibres). 
Branches  of  the  Transverse  Perinceal  Vessels  and  Nerves. 
Base  of  the  Triangular  Ligament  (Urogenital  diaphragm)  (12). 


LITHOTOMY  3Q7 

Membranous  Portion  of  the  Urethra  (2). 
Bulbo-Cavernosus  (Compressor  Urethra)  Muscle. 

Structures  to  be  Avoided  in  Lithotomy.  In  the  Lateral  Operation 
the  structures  to  be  remembered  and  avoided  in  making  the  incision  are 
the— 

Bulb,  its  Artery,  and  the  Rectum, — inwardly  and  in  front;  avoided  by 
not  making  the  primary  incision  too  near  the  middle  line  nor  too  far 
forward. 

Pudlc  Artery  di), — externally;  avoided  by  not  carrying  the  incision  too 
far  outwardly. 

Prostrate  Gland  and  Veins, — behind;  avoided  by  not  carrying  the  deep 
incision  too  far  backward,  so  as  to  cut  through  the  entire  lobe  of  the 
prostate  gland,  permitting  the  urine  to  infiltrate  into  the  loose  areolar 
tissue  around  the  rectum,  instead  of  escaping  externally. 


INDEX 


ABDOMEN,  323 

Regions  of,  323 
Abdominal  Brain,  240 

Cavity,  323 

Openings  of,  324 

Rings,  385,  386 
Acervulus  Cerebri,  194 
Acetabulum,  12 
Achillis,  Tendo,  113 
Adenology,  i 
Ala  Cinerea,  212 
Ala  Lobuli  Centralis,  207 
Alcock's  Canal,  392 
Alveoli,  3,  29,  33 

of  Lungs,  359 

of  Mammary  Gland,  384 
Amphiarthrosis,  59 
Ampulla  of  Fallopian  Tube,  382 

of  Milk  Ducts,  384 

of  Semicircular  Canals,  306 

of  Tubae  Uterinae,  382 
Amygdala,  207,  3M 
Anastomosis,  145 

Circumpatellar,  146 

Crucial,  146 

Elbow,  145 

Hip,  145 

Knee,  146 

Shoulder,  145 

Stirrup,  145 

Tonsillar,  314 

of  Willis,  128,  151 
Anatomy,  i 
Angiology,  i 
Angle,  Filtration,  287 

of  Iris,  287 

of  Jaw,  35 
Ankle-joint,  71 
Annulus,  Ciliaris,  146 

Femoralis,  389 

Fibrosus  Sinister,  121 

Inguinalis  Abdominalis,  385 
Subcutaneous,  386 

Ovalis,  119 
Anterior  Extension  (ischio-rectal  fossa), 

393 

Anti-helix,  297 
Anti-tragus,  297 
Antrum  of  Highmore,  27 

Mastoideum,  301 

Tympanicum,  301 
Anus,  335 
Aorta.  123 

Abdominal,  137.  156 

Arch  of,  123,  449 

Thoracic,  136,  154 


Aortic  Bodies,  345 

Apertura  Pyraformis,  44 

Apertures  in  Abdominal  Wall,  324 

Apex  Capituli,  55 

Appendices  Epiploicae,  328,  335 

Testis.  373 
Appendix  Auriculae,  119 

Ensiform,  8 

Ventriculae,  354 

Vermiform,  334 

Xiphoid,  8 
Aponeuroses,  74 
Aponeurosis,  Pharyngeal,  322 

Vertebral,  90 
Apophysis,  3 

Aquaeduct  of  Sylvius,  202 
Aquaeductus  Cerebri,  202 

Cochleae,  21,  43,  306 

Fallopii,  220,  225 

Vestibuli,  21,  42,  305 
Arachnoid  of  Brain,  181 

of  Cord,  213 

Granulations,  181,  182 
Arbor  Vitae,  208,  380 
Arch,  Carpal,  135 

Crural,  387,  39O 

Glosso-palatine,  314 

Lumbo-costal,  107 

Palmar,  135 

Pharyngo-palatine,  314 

Plantar,  145 

Superciliary,  14 

Volar,  135 
Arcuate  Fibres,  Cerebellar,  208 

Medullary,  210 
Area  Cribrosa,  311 

n.  Facialis,  311 

Vestibularis,  311 
Areola  Mammae,  384 
Arm,  47 
Arnold's  Ganglion,  224 

Nerve,  221,  250 
Arterias  Cavernosae,  127 

Propriae  Renales,  362 

Receptaculi,  127 
Arterial  Anastomoses,  145 

System  Tabulated,  147 
Arteriolae  Rectae,  362 
Artery  or  Arteries,  122,  147 

Acromio-trmracic,  132,  153 

Alar-thoracic,  132,  153 

Alveolar,  Inferior,  126,  150 
Superior,  126,  150 

Anastomoses  of,  145 

Anastomotica  Magna  (arm) ,  133. 1 53 
(thigh),  142,  1 60 


399 


400 


INDEX 


Artery,  Angular,  125,  148 
of  Ankle-joint,  71 
Anonyma,  124,  148 
Antero-lateral  Ganglionic,  127,  151 
Antero-medial  Ganglionic,  127,  151 
Aorta,  123 

Abdominal,  137,  156 

Arch  of,  123,  148 

Thoracic,  136,  154 
Arch,  Palmar    (volar),    Deep,  136, 

153 
Superficial,  135,  154 

Plantar,  145,  162 
Arcuata,  144,  162 
Ascending  Pharyngeal,  125,  150 
of  Auditory  Canal,  298 
Auditory,  Internal,  312 
of  Auricle,  298 
Auricular,  125,  148 

Anterior,  126,  150 

Deep,  126,  150 
Posterior,  125,  150 
Axillary,  132,  153 
Axis,  Coeliac,  137,  156 

Thyroid,  131,  152 
Azygos  of  Knee,  143,  162 

of  Vagina,  139,  379 
Basal,  127 

Basilar,  131,  151,  152 
of  Bladder,  368 
Brachial,  133,  136,  153 
of  Brain,  Cortical,  128 
of  Bones,  4 

Bronchial,  136,  154,  356 
Buccal,  126,  150 
Bulbar,  131,  152 
Bulbi  Urethras,  140,  158 
Calcanean,  144,  162 
Canalis  Pterygoidea,  126,  150 
Carotid,  Common,  124,  148,  150 

External,  125,  148,  150 

Internal,  126,  151 
Carotico-tympanic,  127,  151 
Carpal,  Arch,  Anterior,  135 
Posterior,  135 

Radial,  Anterior,  133,  153 
Posterior,  134,  153 

Ulnar,  Anterior,  135,  154 

Posterior,  135,  154 
Cavernosae,  127,  151 
Centralis  Retinas,  127,  289 
Cerebellar,    Anterior-inferior,    131, 
152 

Posterior-inferior,  131,  152 

Superior,  131,  152 
Cerebral,  Anterior,  127,  151 

Middle,  127,  151 

Posterior,  128,  152 
Cervical,  Ascending,  131,  152 

Deep,  from  Sup.  Intercostal,  132 

Superficial,  131,  152 

Transverse,  131,  152 
Choroid,  Anterior,  128,  151,  283 

Posterior,  128,  152 
Ciliary,  Anterior,  127,  290 

Long,  127,  290 

Short,  127,  290 
Circle  of  Willis,  128,  151 


Artery,  Circulus  Major  and  Minor,  285 
Circumflex,   Femoral,  Lateral,  142, 

160 
Medial,  142,  160 

Humeral,  Anterior,  133,  153 
Posterior,  133,  153 

Iliac,  Deep,  141,  160 
Superficial,  141,  160 

Scapulae,  132,  153 
Coccygeal,  140,  158 
Cochlear,  312 
Coeliac  Axis,  137,  156 
Colic,  Left  (sinistra),  138,  156 

Middle  (media),  138,  156 

Right  (dextra),  138,  156 
Comes  Nervi  Ischiadici,  140,  158 

Phrenici,  132,  152 
Communicating,     Cerebral,     Ante- 
rior, 127, 152 
Posterior,  127,  151 

of  Palmar  Arches,  135,  154 

of  Plantar  Arch,  144,  162 
Coronary,  of  Heart,  123,  148 

of  Lips,  125,  148 
of  Corpus  Cavernosum,  130,  158 
Cortical  System  of  Brain,  128 
Cremasteric,  141,  160 
Cricq-thyro'd,  125,  148 
Cystic,  138,  156 
Dental,  Inferior,  126,  150 

Superior,  126,  150 
Digital,  Palmar  Collateral,  135,  154 

Plantar  Collateral,  145,  162 
Dorsalis  Clitoridis,  140,  158 

Hallucis,  144,  162 

Indicis,  134,  153 

Linguae,  125,  148 

Nasi,  127,  151 

Pedis,  143,  162 

Penis,  140,  158 

Pollicis,  134,  153 

Scapulae,  132,  153 
of  Ear,  301,  312 
of  Elbow,  66,  145 
Epigastric,  Deep,  140,  160 

Inferior,  140,  160 

Superficial,  141,  160 

Superior,  132,  152 
Ethmoidal,  Anterior,  127,  151 

Posterior,  127,  151 
of  Eustachian  Tube,  304 
of  Eye,  289 
Facial,  Deep,  126,  151 

Superficial,  125,  148 

Transverse,  126,  150 
Femoral,  Common,  141 

Deep  (profounda),  142,  160 

Superficial,  141,  160 
Fibular,  144,  162 
of  Foot,  143,  144 
of  Forearm,  133,  153 
Frontal, from  Ant.  Cerebral,  127, 151 
Mid.  Cerebral,  127,  151 
Ophthalmic,  127,  151 
Temporal,  126,  150 
Ganglionic,  Antero-lateral,  127,  151 

Postero-lateral,  128,  152 

Antero-medial,  127,151 


INDEX 


4OI 


Artery,  Ganglionic,  Postero-medial,  128, 
152 

System  of  Brain,  128 
Gastric,  137,  150 
Gastric,  Left,  137,  156 

Right,  137,  156 
Gastricae  Breves,  138,  156 
Gastro-duodenal,  137,  156 
Gastrp-epiploica  Dextra,  137,  156 

Sinistra,  138,  156 
Genu  Suprema,  142,  160 
Gluteal,  Inferior,  140,  158 

Superior,  140,  160 
Haemprrhoidal,  Inferior,  140,  158 

Middle,  139,  158 

Superior,  138,  156 
of  Hand,  135 
of  Head,  124 
of  Heart,  119 
Helicine,  371 
Hepatic,  137,  138,  158,  340 

Left,  138,  156 

Right,  138,  156 
of  Hip-joint,  68,  145 
Hyoid,  from  Lingual,  125,  148 

from  Superior  Thyroid,  125,  148 
Hypogastric,  139,  158,  160 
Ileo-colic,  138,  156 
Iliac,  Circumflex,  Deep,  141,  160 
Superficial,  141,  160 

Common,  139 

External,  140,  160 

Internal,  139,  158,  160 
Ilio-lumbar,  140,  160 
Incisor,  126,  150 
Infra-orbital,  126,  150 
Innominate,  124,  148 
Intercostal,  136,  154 

Anterior,  132,  152 

Perforating,  132,  152 

Superior,  132 

Intercostalis  Suprema,  132 
Internal  Auditory,  312 
Interosseous,  Common,  134 

of  Foot,  144,  162 

of  Forearm,  134,  154 

of  Hand,  134,  152 

Ulnar,  134,  154 
Intestines,  333,  336 
Intestini  Tenuis,  138,  156 
of  Iris,  285 
of  Kidney,  364 
of  Knee,  69,  143,  145,  162 
Labial,  Coronary,  125,  148 

Inferior,  125,  148 
Labiales,  125 
of  Labyrinth,  312 
Lacrimal,  127,  151 
Laryngeal,  Inferior,  131,  152 

Superior,  125,  148 
of  Larynx,  354 
Lateralis  Nasi,  125,  148 
Lenticulo-striate     (ant.-lat.     gang- 

lionic),  127 
Lienal,  138,  156 
Lingual,  125,  148 

Dorsal,  125,  148 
of  Liver,  341 
20 


Artery,  of  Lower  Extremity,  141 
Lumbar,  138,  156,  160 
of  Lungs,  359 
Magna,  153 
Malleolar,  Lateral,  143 

Medial,  143 
Mammary,  External,  132 

Internal,  131,  152 
of  Mammary  Gland,  384 
Mandibular  (inf.  dental),  126,  150 
Masseteric,  126,  150 
Mastoid,  125,  150 
Maxillary,  External,  125,  148 

Internal,  126,  150 
Median,  134 
Mediastinal,  132,  152 

Posterior,  136,  154 
of  Membrana  Tympani,  299 
Meningeal,  Anterior,  127,  151 

Middle,  126,  150 

from  Occipital,  125,  148 

from  Pharyngeal,  125,  150 

Posterior,  131,  152 

Small,  126,  150 

from  Vertebral,  131,  152 
Mental,  126,  150 
Mesenteric,  Inferior,  138,  156 

Superior,  138,  156 
Metacarpal,  134,  153 
Metatarsal,  144,  162 
Musculo-phrenic,  132,  152 
Mylo-hyoid,  126,  150 
Nasal,  Dorsal,  127,  151 

Lateral,  125,  148 

from  Ophthalmic,  127,  151 
of  Nasal  Fossae,  279 
of  Neck,  124 
of  Nose,  279 
Nutrient  of  Clavicle,  131,  152 

of  Femur,  142,  160 

of  Fibula,  144,  162 

of  Humerus,  133,  153 

of  Tibia,  144,  162 
Obturator,  139,  158,  389 
Occipital,  125,  148 
CEsophageal,  131,  136,  152,  154 
of  (Esophagus,  323 
Ophthalmic,  127,  151 
Orbital,  127,  151 
Ovarian,  138,  156 
of  Ovaries,  383 
Palatine,  Ascending,  125,  148 

Descending,  126,  150 

Inferior,  125,  148 

Posterior,  126,  150 
Palmar  (volar)  Arch,  Deep,  136 

Superficial,  135 
Recurrent,  134,  153 
Palpebral,  127,  151 
of  Pancreas,  344 
Pancreaticae  magnae,  138 

Parvae,  138 

Pancreatico-duodenal,          Inferior, 
138,  156 

Superior,  137,  156 
Parietal,  126,  151 
Parieto- temporal,  127.  151 
of  Parotid  Gland,  126,  316 


402 


INDEX 


Artery,  of  Pelvis,  139 
of  Penis,  372 

Perforating,   Anterior    Intercostal, 
132, 152 

of  Foot,  145,  162 

of  Hand,  134,  153 

of  Thigh,  142,  1 60 
Pericardiac,  132,  152 
Pericardia!,  136,  15,1 
Pericardio-phrenic,  132 
of  Pericardium,  118 
Perinaeal,  Superficial,  140,  158 

Transverse,  140,  158 
of  Perineum,  140 
Peroneal  (fibular),  144,  162 
Pharyngeal,  125,  126,  150 

Ascending,  125,  150 
of  Pharynx,  322 
of  Pia  Mater,  182 
Plantar,  Lateral,  144,  162 

Medial,  14.4,  162 
Popliteal,  143,  162 
Postero-lateral  Ganglionic,  128,  152 
Postero-medial  Ganglionic,  128,  152 
Prevertebral,  125,  150 
Princeps  Cervicis,  125,  148 

Polhcis,  134,  153 
Profunda  Brachii,  133,  153 

Cervicis,  132 

Femqris,  142,  160 

Inferior  (arm),  133,  153 

Penis,  140,  158 

Superior  (arm),  133,  153 
of  Prostate  Gland,  370 
Pterygoid,  126,  150 
Pterygo-palatine,  126,  150 
Pubic,  141,  160 
Pudendal,  139,  158 
Pubic,  External,  Deep,  142,  160 
Superficial,  141,  160 

Internal,  139,  158 
Pulnumary,  122,  147 
Pyloric,  137,  156 
Radial,  133,  153 
Radialis  Indicis,  134,  153 
Radial  Recurrent,  133,  153 
Ranine,  125,  148 
Receptaculi,  127,  151 
Recurrent,  Palmar  (volar),  134,153 

Radial,  133,  153 

Tibial,  Anterior,  144,  162 
Posterior,  144,  162 

Ulnar,  Anterior,  134,  154 
Posterior,  134,  154 

Volar  (palmar),  134,  153 
Renal,  138,  156 
Rete  Carpi  Dorsale,  135 

Volare,  135 
of  Retina,  286 
Sacral,  Lateral,  140,  160 

Middle,  138,  156 
Scapular,  Circumflex.  132,  153 

Dorsal,  132,  153 

Posterior,   131,   152 

Transverse,     131 
Sciatic,  140,  158 
of  Shoulder-joint,  65,  145 
Sigmoid,  138,  156 


Artery,  Spermatic,  138,  156 
of  Spermatic  Cord,  377 
Spheno-maxillary,  126,  150 
Spheno-palatine,  126,  150 
Spinal,  Anterior,  131,  152 

Lateral,  131,  152 

Posterior,  131,  152 
of  Spleen,  349 
Splenic,  138,  156 
Sternal,  132,  152 
Sterno-mastoid,  125,  148 
of  Stomach,  330 
Stylo-mastoid,  125,  150 
Subclavian,  130 
Subcostal,  136 
Sublingual,  125,  i/>8 
Submandibular,  125,  148 
Submental,  125,  148 
Subscapular,  132,  153 
Superficialis  Volas,  133,  153 
Supra-orbital,  127,  151 
Supra-renal,  138,  156 
of  Supra-renal  Gland,  365 
Supra-scapular,  131,  152 
Sural,  143 

Tables  of  the  Arterial  System,  147 
Tarsal,  144 

Temporal,  Deep,  Anterior,  126,  150 
Posterior,  126,   150 

Middle,  126,  150 

Superficial,  126,  150 
of  Testicle,  375 
of  Thigh,  141,  1 60 
Thoracalis  Lateralis,  132 

Suprema,  132 
Thoracic,  Acromio,  132,  153 

Alar,  132,  153 

Axis,  131,  153 

Long,  132,  153 

Superior,  132,  153 
Thoraco-acromial,  132 
of  Thymus  Gland,  346 
Thyroid.  Axis,  131 

Inferior,  131,  152 

Superior,  125,  148 
of  Thyroid  Gland,  346 
Thyroidea  Ima,  124 
Tibial,  Anterior,  143,  16^ 

Posterior,  144,  162 

Recurrent,  Anterior,  143,  162 

Posterior,  143,  162 
of  Tongue,  275 
Tonsillar,  125,  148 

True,  314 
of  Tonsils,  314 
of  Trachea,  356 
Tracheal,  131,  152 
Transversalis  Colli,  131,  152 

Scapulae,  131 
True  Tonsillar,  314 
Truncus  Thyreo-cervicalis,  131 
of  Trunk,  136 
Tympanic  from  Ascending 
Pharyngeal,   125,   150 

from  Internal  Carotid,  127,  151 

Maxillary,  126,  150 
of  Tympanic  membrane,  299 
of  Tympanum,  302 


INDEX 


403 


Artery,  Ulnar,  134,  IS4 

Carpal,  134,  154 

Collateral,  133 

Interosseous,  134 

Recurrent,  Anterior,  134,  154 

Posterior,  134,  154 
of  Upper  Extremity,  130 
Urethral,  140 
Uterine,  139,  158 
of  Uterus,  382 
of  Vagina,  379 
Vaginal,  139,  158 
Vasa  Brevia,  138,  156 

Intestinales,  138 

Intestini  Tenuis,  138,  156 

Vasorum,  122 
of  Vas  Deferens,  139,  158 
Vertebral,  131,  152 
Vesical,  Inferior,  139,  158 

Middle,  139,  158 

Superior,  139,  158 
of  Vesiculae  Seminales,  377 
Vidian,  126,  150 
Volar,  Superficial,  133,  153 
Willis,  Circle  of,  128,  251 
Zygomatico-orbital,  126 
Arthrodial  joints,  59 
Articulations,  59 

Acromio-clavicular,  65 
Ankle,  71 

Astragalo-navicular,  72 
Atlanto-axial,  58 
Atlanto-epistrophica,  61 
Calcaneo-astragaloid,  72 
Calcaneo-cuboid,  72 
Calcaneo-navicular,  72 
Carpal,  50,  67 
Carpo-metacarpal,  68 
Chondro-sternal,  62 
Costo-chrondal,  62 
Costo-transverse,  62 
Costo-vertebral,  62 
Elbow,  66 
Hip,  68 
Intercarpal,  67 
Interchondral,  62 
Knee,  69 

Metacarpo-metacarpal,  68 
Metatarso-metatarsal,  73 
Motion  in,  60 
Occipito-atlantal,  62 
Occipito-axial,  62 
Phalangeal  of  Foot,  73 

of  Hand,  68 
Pubic,  64 
Radio-carpal,  67 
Radio-ulnar,  66 
Sacro-C9ccygeal,  63 
Sacro-iliac,  64 
Sacro-ischiatic,  64 
Sacro- vertebral,  63 
Scapulo-clavicular,  65 
Shoulder,  65 
Sterno-clavicular,  64 
Structure  of,  60 
Tarsal,  57,  72 
Tarso-metatarsal,  72 
Ternporo-mandibular,  6q 


Articulations,  Tibio-fibular,  71 

of  the  Trunk,  60 

Vertebral,  61 
Arytenoid  Cartilages,  351 
Astragalus  (talus),  57 
Atic,  300 
Atlas,  6 
Atrium  Meatus  Medii  Nasi,  278 

Tympani,  300 
Auricle  of  Ear,  297 

of  Heart,  119 
Auris  Externa,  296 

Interna,  304 

Media,  300 
Axis,  7 

Caeliac,  137,  156 

Thyroid,  131,  152 
Axis-cylinders,  177 
Axones,  177 
Azygos,  3 

BAND,  Bellinger's,  285 

Naso-labial,  78 
Bartholin,  Duct  of,  317 

Glands  of,  378 
Basal  Ganglia,  179 
Base  of  the  Brain,  186 

,  of  the  Skull,  41 
Basi-hyal,  41 

Basis  Pedunculi  Cerebri,  195 
Bauhin,  Valve  of,  334 
Bell,  Sir  Charles,  Nerve  of,  229,  256 
Bertin,  Columns  of,  361 
Bladder,  Gall,  193  -  *J  f  J 

Urinary,  365 
Blandin,  Glands,  of,  274 
Blastema,  4 

Blood- vascular  System,  118 
Body  or  Bodies,  Aortic,  345 

Carotid,  345 

Chromaphil,  345 

Ciliary,  283 

Coccygeal,  349 

Gemculate,  193 

Malpighian,  349,  361 

Mammillary,  188 

Olivary,  209 

Perinseal,  395 

Pineal,  194 

Pituitary,  186 

Quadrigeminal,  202 

Restiform,  207,  209 

Vitreous,  287 

Wolffian,  383 
Bone  or  Bones,  i 

Astragalus  (talus),  57 

Atlas,  6 

Axis  (epistropheus),  6 

Calcaneus,  57 

Cancellous  Bones,  2 

Capitate  (Magnum),  51 

Cavities  of,  3 

Clavicle,  45 

Classification  of,  i 

Coccyx,  ii 

Composition  of,  3 

Costae,  8 

Coxae  or  Coxal ,  1 1 


404 


INDEX 


Bones,  Cuboid,  57 

Cuneiform  (carpal),  51 

(tarsal),  57 
Eminences  of,  3 
Enumeration  of,  i 
Epistrqpheus  (axis),  6 
Ethmoid,  26 
Femur,  52 
Fibula,  55 
Flat  Bones,  2 
Frontal,  14 

Hamate  (unciform),  51 
Histology  of  Bone,  3 
Humerus,  47 
Hyoid,  41 
Ilium,  13 
Incus,  301 

Innominate  (coxal),  II 
Irregular  Bones,  2 
Ischmm,  13 
Lacrimal,  29 
Long  Bones,  i 
Lunate  (Semilunar),  51 
Malar,  30 
Malleus,  301 
Mandible,  33 
Marrow  of  Bones,  4 
Maxilla,  27 
Medullated  Bones,  i 
Metacarpals,  51 
Metatarsals,  58 
Multangular,  Great,  51 

Small,  51 
Nasal,  27 
Navicular  (carpal),  51 

(tarsal),  57 
Occipital,  17 
Orbicular,  301 
Os  Calcis,  57 
Os  Capitatum,  51 
Os  Coccygis,  1 1 
Os  Coxae,  n 
Os  Hamatum,  51 
Os  Innominatum,  n 
Os  Lunatum,  51 
Os  Magnum,  51 
Os  Multangulum  Majus,  51 

Minus,  51 
Os  Nayiculare,  51 
Os  Orbiculare,  301 
Os  Triquetrum,  51 
Ossa  Suturarum,  40 
Ossification  of  Bones,  4 
Palate,  31 
Parietal,  16 
Patella,  54 
Pectineal,  14 
Peroneal,  55 
Petro-mastoid,  19 
Phalanges  of  Foot,  58 

of  Hand,  52 
Pisiform,  51 

Prominences  of  Bones,  3 
Pubic,  14 
Radius,  49 
Ribs  (costse),  18 
Sacral,  10 
Scaphoid  (carpal),  51 


Bones,  Scaphoid  (tarsal),  57 

Scapula,  45 

Semilunar,  51 

Sesamoid,  3 

Short  Bones,  i 

Squamous,  19 

Stapes,  301 

Sternum,  8 

Structure  of  Bone,  4 

Talus,  57 

Temporal,  19 

Tibia,  54 

•Trapezium,  51 

Trapezoid,  51 

Triquetral  (cuneiform),  51 

Turbinal,  32 

Tympanic,  19 

Ulna,  48 

Unciform,  51 

Unclassified  Bones,  3 

Vertebrae,  5 

Vomer,  33 

Wormian,  3,  AO 

Zygomatic,  30 
Bowman's   Capsule,  361 

Glands,  279 

Muscle  (ciliary),  284 

(cochlear),  309 
Brachia  Conjunctiva,  201,  207 

Pontis,  204,  207 
Brain,  178 

Abdominal,  240 

Basal  Ganglia  of,  179 

Cerebellum,  206 

Cerebrum,  183 

Convolutions  of,  185 

Cortex  of,  179 

Development  of,  178 

Diencephalon,  178 

Divisions  of,  178,  182 

Fissures  of,  184 

Gray  Matter  of,  179 

Hind-brain,  203 

Hypophysis  Cerebri.  186 

Island  of  Reil,  183 

Isthmus  Cerebri,  194 

Isthmus  Rhombencephali,  178,  203 

Lobes  of,  183 

Medulla  Oblongata,  208 

Meninges  of,  180 

Mesencephalon,  178,  194 

Metencephalon,  178,  203 

Mid-brain,  178,  194 

Myelencephalon,  178,  208 

Points  on  Under  Surface,  186 

Pons  Varolii,  203 

Prosencephalon,  178 

Rhombencephalon,  192 

Telencephalon,  178 

Thalamencephalon,  192 

Under  Surface  of,  186 

Weight  of  Average  Brain,  182 

White  Matter  of,  179 

Ventricles  of,  189 

Vesicles  of,  178 
Breasts,  383 

Broca's  Area  or  Convolution,  185 
Bronchi,  355 


INDEX 


405 


Bruch's  Membrane,  283 

Brunner's  Glands,  333 

Buccae,  312 

Buck's  Fascia,  393 

Buds,  Taste,  274 

Bulb  of  Corpus  Spongiosum,  372 

Olfactory,  183 

Spinal,  208 

Urethra],  369 
Bulbus  Oculi,  280 

Vestibuli,  378 
Bulla  Ethmoidalis,  277 
Bundle,  Ground,  215 

Posterior  Longitudinal,  200 
Burns'  Ligament,  390 
Bursa  Omentalis,  325 

Pharyngea,  321 
Bursae  of  Knee-joint,  71 


Calamus  Scriptorius,  211 

Calcaneus,  57 

Calcar  Avis,  191 

Calcar  Femorale,  53 

Calices  of  Kidney,  361 

Cameras  Oculi,  287 

Camper's  Fascia,  108,  385 

Canal,  or  Canalis,  Adductor,  no,  142 

Alcock's,  392 

Alimentary,  312 

Anal,  335 

of  Arnold's  Nerve,  21 

Carotid,  20 

Central  of  the  Cord,  214 

Centralis  Modioli,  306 

Cervicis  Uteri,  380 

Condyloideus  Posterior,  18 

Crural,  388 

Dental,  27 

Facial,  220,  225 

Femoral,  388 

Haversian,  4 

of  Huguier,  19 

Hunter's,  no,  142 

Hyaloid,  288 

Hypoglossi,  1  8 

Infra-orbital,  28 

Inguinal,  385 

of  Jacobson's  Nerve,  21 

Lacrimal,  295 

of  Laxator  Tympani,  19,  43 

Malar,  30,  36 

Mandibular,  34 

of  the  Modiolus,  306 

of  Nuck,  381 

Palatine,  28 

Petit's,  288,  289 

Pharyngeal,  32 

Pterygoideus,  25 

Ptery  go-palatine,  28 

Reuniens,  307,  308 

Sacral,  n 

of  Schlemm,  282 

Semicircular,  305,  308 

Spheno-palatine,  32 

Spiral  of  Cochlea,  306 

Stilling's,  288 

for  Tensor  Tympani,  301 


Canal,  Vidian,  25 

Zygomatico-facial,  30,  36 

Zygomatico-temporal,  36 
Canaliculi  Dentales,  319 

Lacrimal,  295 
Canthus  (eye),  293 
Capillaries,  Biliary,  340 

Blood,  122 

Capitellum  Humeri,  48 
Capsule  or  Capsula,  Bowman's,  361 

External,  192 

of  Glisson,  340 

Glomeruli,  361 

Internal,  192 

Lentis,  288 

Tenon's,  280 

Supra-renal,  364 
Caput  Gallinaginis,  368 
Cardia,  329 
Carpus,  50 
Cartilage  or  Cartilage,  60 

Arytenoid,  351 

Corniculata,  352 

Cricoid,  351 

Cuneiform,  352 

Epiglottica,  352 

of  Larynx,  350 

Santorini's,  352 

Thyroid,  350 

Triticea,  353 

Varieties  of,  60 

Wrisberg's,  352 
Carunculae  Humenales,  378 

Lacrimal,  295 

Myrtiformes,  378 
Cauda  Equina,  216 
Cavity  or  Cavum — 

Abdominal,  323 

Acetabular,  12 

Cotyloid,  12 

Dentis,  318 

Glenoid,  47 

Omental,  325 

Oris,  312 

Pelvic,  391 

Peritonaei,  325 

Pulp,  318 

Septi  Pellucidi,  191 

Sigmoid  of  Radius,  50 
of  Ulna,  49 

Subarachnoidalis,  181 

Subdurale,  181 

Tympanic,  300 

Uteri,  380 
Cells,  Air,  359 

Auditory,  310 

Claudius',  310 

Deiters',  310    . 

Ethmoidal,  26 

Golgi's,  176,  208 

Hair,  307,  310 

Hensen's,  310 

Hepatic,  340 

Mastoid,  20 

Nerve,  176 

Olfactory,  278 

Purkinje's,  176,  208 

Reticular,  349 


406 


INDEX 


Cells,  Sustentacular,  349 

Cement,  319 

Cerato-hyal,  41 

Cerebellum,  206  (see  Brain) 

Cerebro-spinal  System,  175 

Cerebrum,  179  (see  Brain) 

Cervic  Penis,  372 

Cervix  Uteri,  380 

Chambers  (camerae)  of  the  Eye,  287 

Chiasm,  Optic,  292 

Chorda  Tympani,  220,  248,  276 

Chordae  Tendinae,  120 

Choroid,  283 

Plexus,  190,  211 
Chromaffin  System,  344 
Chromaphil  System,  344 
Cilia,  293 
Ciliary  Body,  283 
Cingulum,  180 
Circle  of  Willis,  128,  151 
Circulation,  Collateral,  146 
Circulus  Major  of  Iris,  285 

Minor  of  Iris,  285 

Venosus,  384 
Cisterna  Chyli,  172 

Cerebello-medullaris  (magna),  182 

Inter-peduncularis,  182 

Magna  (cerebello-medullaris) ,  182 
Clarke's  Column,  210,  216 
Claudius'  Cells,  310 
Claustrum,  192 
Clava,  198 
Clavicle,  45 
Clinoid,  3 
Clitoris,  378 
Clivus  Monticuli,  207 
Cloquet's  Fascia,  389 
Coccygis,  ii 
Coccyx,  ii 
Cochlea,  306,  309 
Collar-bone,  45 
Collateral  Circulation,  146 
Colics'  Fascia,  392 
Colliculi  (quadrigemina),  202 
Colliculus  Nervi  Facialis,  212 
Optici,  286 

Semmalis,  368 
Colloid,  346 
Collum  Glandis,  372 
Colon,  334 
Column  or  Columns — 

Antero-lateral  of  Cord,  214 

Bertin's,  361 

Burdach's,  198,  210,  215 

Clarke's,  210,  216 

Coil's,  198,  210,  215 

Lateral  of  Medulla,  209 

Posterior  of  Cord,  214 
Vesicular  (Clarke's),  216 

Postero-lateral  of  Cord,  214 

Postero-median  of  Cord,  214 

of  Spinal  Cord,  213 

of  Vagina,  379 
Columnae  Carneae,  120,  122 

Rugarum,  379 
Commissura  or  Commissure — 

Anterior  (yhite)     of    3d  Ventricle, 
192 


Commissura,  Gray  (middle)  of  3d  Ven- 
tricle, 193 

Gudden's,  194,  292 

Labiorum  Pudendi,  377 

Meynert's,  292 

Middle  (gray)  of  3d  Ventricle,  193 

Optic,  1 86,  292 

Palpebrarum,  293 

Posterior  (white)  of  3d  Ventricle,  193 
Concha  or  Conchae — 

Auriculas,  297 

Nasalis,  26,  32 

Sphenoidal,  24 
Conductor  Sonorus,  212 
Condyle,  3 

Condyloid  Articulations,  59 
Confluens  Sinuum,  165 
Coni  Vasculosi,  374 
Conjoined  Tendon,  95 
Conus  Arteriosus,  120 

Elasticus,  353 
Convolution  of  Broca,  185 
Convolutions  of  the  Cerebrum,  185 
Cooper's  (Sir  Astley)  Fascia,  390 
Cor,  118 
Coracoid,  3 
Cord,  Gangliated,  237 

Spermatic,  376 

Spinal,  213 
.Vocal,  353 
Conum,  270,  271 
Cornea,  282 

Cornicula  Laryngis,  352 
Cornua  of  Hyoid,  41 

Uteri,  380 

Ventricular,  190 
Corona  Glandis,  372 

Radata,  196 
Coronoid,  3 
Corpora  Albicantia,  188 

Amylacea,  194 

Cavernosa,  371 

Geniculata,  193 

Mammillaria  (albicantia),  188 

Quadrigemina  (colliculi),  202 

Restiformes,  207,  209 
Corpus  Albicans,  383 

Callosum,  190 

Cayernosum  Urethras,  371 

Ciliare,  283 

Dentatum,  209 

Fimbriatum,  190,  191 

Highmorianum,  374 

Luteum,  383 

Mammae,  384 

Medullare,  206 

Pineale,  194 

Striatum,  191 

Trapezoideum,  204 

Uteri,  380  . 

Vitreum,  287 
Corpuscles,  Cprneal,  282 

Ganglionic,  176 

Pacinian,  272 

Tactile,  272 
Cortex,  Cerebellar,  208 

Cerebral,  179 

Renal,  361 


INDEX 


407 


Corti,  Organ  of,  309 
Cortical  System,  345 
Costae  (ribs),  8 
Cotyloid.  3 

Cavity,  12 

Notch,  12 
Coverings  of  Brain,  180 

of  Femoral  Hernia,  390 

of  Inguinal  Hernia,  388 

of  Testicles,  373 

of  Spinal  Cord,  213 
Cowper's  Glands,  371 
Coxal  or  Hip-bone,  n 
Crest,  Conchal,  27,  31 

of  Ilium,  13 

Infra-temporal,  24 

Inter-trochanteric,  53 

Nasal,  29 

Nuchal,  17 

of  Pubis,  17 

Sphenoidal,  23 

Tibial,  55 

Turbinal,  27,  31 
Cribriform  Fascia,  108,  390 

Plate,  26 

Cricoid  Cartilage,  351 
Crista  Falciformis,  311 

Galli,  26 

Transversa,  311 

Urethrae,  368 

Vestibuli,  305 
Crucial  Anastomosis,  146 

Ridge,  1 8 
Crura  of  Abdominal  Ring,  386 

Cerebri,  195 

Clitoridis,  378 

of  Diaphragm,  95 

of  Penis,  371 
Crus  Commune,  306 
Crusta  Cerebri,  195 

Petrosa,  319 

Crypts,  of  Lieberkuhn,  332 
Cuboid,  57 

Culmen  Monticuli,  207 
Cuneus,  186 
Cupola  Cochleae,  306 
Cushion,  Pharyngeal,  321 
Cuticle,  268 
Cuticuta  Dentis,  319 
Cutis  Vera,  270 

DARTOS,  373 

Darwin's  Tubercle,  297 

Decussation,  Inferior  Pyramidal,  209 

Motor,  209 

Sensory,  198 

Superior  Pyramidal,  198 
Deiter's  Cells,  310 
Dendrites,  177 
Dentes,  317 
Dentine,  318 
Derma,  270 
Dermatology,  I 
Descemet's  Membrane,  282 
Diaphragm,  94 

Urogenital,  393 
Diaphragma  Sellae,  181 
Diaphysis,  9 


Diarthrosis,  59 
Diclive,  207 
Diencephalon,  178,  192 
Discus  Proligerus,  383 
Disk,  Intervertebral,  61 

Optic,  286 
Diverticulum  Ilei,  331 

Meckel's,  331 
Dollinger's  Band,  285 
Dorsum  Sellae,  23 
Douglas'  Pouch,  327 

Semilunar  Fold,  96 
Drum  of  the  Ear,  300 
Drum-head,  298 
Duct,  Ducts,  or  Ductus — 

Aberrans,  373 

Arteriosus,  123 

Bartholin's,  317 

Biliary,  342 

Cochlearis,  307 

Communis  Choledochus,  342 

Cowper's,  368 

Cystic,  343 

Deferens,  375 

Ejaculatory,  368,  376 

Endo-lymphaticus,  308 

Gartner's,  383 

Hepatic,  342 

Lactiferi,  384 

Lymphatic,  172 

Lymphaticus  Dexter,  172 

Nasal,  28,  296 

Naso-lacrimal,  296 

Pancreatic,  344 

Parotideus,  316 

Prostatic,  370 

Rivinius",  316 

Santorini's,  344 

Semicirculares,  307,  308 

Stenson's,  316 

Sublinguales  Minores,  316 

Sublingualis,  316 

Submaxillaris,  316 

Thoracic,  172 

Wharton's,  316 

Wirsung's,  344 

Utriculo-saccularis,  308 
Ductless  Glands,  344 
Duodenum,  331 
Dural  Sinuses,  164,  165 
Dura  Mater  Cerebri,  180 
Spinalis,  213 

EAR,  296 

External,  297 

Internal,  304 

Middle,  300 
Elbow-joint,  66 
Eleidin,  270 
Eminence,  Frontal,  14 

Hypothenar,  106 

Malleolar,  298 

Nasal,  14 

Eminence  Parietal,  16 

Pectineal,  14 

Thenar,  196 
Eminentia  Articularis,  19 

Cinprea .  v  i  • 


INDEX 


Eminentia  Collateralis,  191 

Inter-cpndyloidea,  54 

Pyramidalis,  301 

Saccularis,  186 

Teres,  212 
Enamel,  319 
Enarthrosis,  59 
End-bulbs  of  Krause,  177,  272 
Endocardium,  118 
Endolymph,  304 
Endomysmm,  74 
Endoneurium,  177 
End-organs  of  Nerves,  177 
Endosteum,  4 
Ensiform  (xyphoid),  8 
Epidermis,  270 
Epididymis,  373 
Epigastric  Region,  324 
Epiglottis,  352 
Epineurium,  177 
Epiphysis,  3 

Cerebri,  194 

Epistropheus  (axis),  6,  7 
Equilibration,  Organ  of,  309 
Ethmoid,  26 
Eustachian  Tube,  303 
Eye,  280 


Eyebrows,  293 

Eyelashes,  293 

Eyelids,  293 

Eye-socket  (orbit),  35 

Excavatio  Papillae  Nervi  Optici,  286 

Recto-uterina,  327 

Recto-  vesicalis,  327 

Vesico-uterina,  327 
Extension,  Anterior  of  Ischio-rectal 
Fossa,  394 

FACET,  3 

Fallopian  Tubes,  382 

Fallopius,  Aquseduct  of,  220,  225 

Hiatus  of,  20 
Falciform  Process,  390 
Falx  Aponeurotica  Inguinalis,  95 

Cerebelli,  181 

Cerebri,  181 
Fascia,  Anal,  392 

Bicipital,  133 

Buck's,  393 

Bulbi  Oculi,  280 

Camper's,  108,  385 

Cloquet's,  389 

Colles',  392 

Cooper's,  390 

Cremasteric,  386 

Cribriform,  108,  390 

Deep,  74 

Dentate,  191 

Diaphragmatis  Urogenitalis,  393 

Dorsal,  90 

Infundibuliform,  385 

Iliac,  107 

Intercolumnar,  386 

Ischio-rectal,  392 

Lata,  1  08,  199 

Lumbar,  90 


Fascia,  Lumbo-dorsal,  90 
Naso-labial  Band,  78 
Obturator,  391 
Palmar,  105 
Parotid,  315 

Parotideo-masseteric,  315 
Pelvic,  391 
Perinaeal,  Deep,  393 

Superficial,  392 
Pharyngo-basilar,  322 
Plantar,  115 
Recto- vesical,  391 
Scarpa's,  108,  390 
Spermatic,  386 
Superficial,  74 
Trartsversalis,  107,  390 
Triangular,  387 
Fasciae,  74 

of  the  Back,  90 
of  the  Foot,  115 
of  the  Hand,  105 
of  the  Pelvis,  391 
of  the  Perinaeum,  392 
of  the  Thigh,  108 
Fasciculus,  see  also  Tract 

Anterior  Cerebro-soplina,  96,  214 
Cerebello-olivary,  211 
Cerebro-spinalis  Anterior,  196,  214 

Lateralis,  196,  214 
Crossed  Pyramidal,  196,  214 
Cuneatus  (Burdach's),  198,  210,  215 
Direct  Cerebellar,  210 
Direct  Pyramidal,  196,  214 
Dorsal  Spino-cerebellar,  210 
Fillet,  198 
Flechsig's,  210 
Geniculate,  196 
Geniculate,  196 
Gower's,  205 
Gracilis  (Coil's  column),  198,  210, 

215 

Inferior  Longitudinal,  180 
Lateral  Cerebro-spinal,  196,  214 

Lemniscus,  199 
Lemniscus,  (fillet),  198 
Medial  Lemniscus,  198 

Longitudinal,  200 
Meynert's,  292 
Olivary,  202 
Olivo-cerebellar,  210 
Perpendicular,  180 
Posterp-lateral,  215 
Proprii,  215 
Proprius  Anterior,  215 

Dorsalis,  215 

Posterior,  215 

Ventralis,  215 

Retroflexus  (Meynert's),  29 
Rolando's,  209 
Rubro-Spinal,  201 
Solitary,  211,  221 

Spino-cerebellar,  Anterior,  205,  210, 
214 

Dorsal,  210,  215 
Sulco-marginal,  199 
Superficial  Ventro-lateral  (Gower's) 

295,  206 
Superior  Longitudinal,  180 


INDEX 


409 


Fasciculus,  Teres,  205 

Tri-neural,  211 

Tiirck's,  196 

Uncinate,  180 

Ventral  Cerebro-spinal,  196 

Longitudinal,  199 
Fauces,  314 
Femur,  52 
Fenestra  Cochleae,  21,  300 

Ovalis,  300 

Rotunda,  300 

Vestibuli,  21,  300 
Ferrein's  Pyramids,  362 
Fibrae  Propriae,  207 
Fibres,  Arcuate  of  Cerebellum,  208 
of  Medulla,  210 

Association,  180 

Commissural,  180 

Medullated,  17? 

Miiller's,  286 

Nerve,  177 

Non-medullated,  177 

Peduncular,  179,  207 

Projection,  179,  192 

Transverse,  180 
Fibro-cartilage,  60,  70 
Fibula,  55 
Fillet,  Lateral,  199 

Medial,  198 
Filum  Terminale,  213 
Fimbria  Ovarica.  382 
Fimbriae  Tubae  Uterinas,  382 
Fissure,  Auricular,  21,  43 

Ethmoidal,  41 

Glaserian,  19,  43 

Orbital,  25,  36,  39,  41 

Palpebral,  293 

Pterygo-maxillary,  39 

Rolando's,  184 

Sphenoidal,  25,  36,  41 

Spheno-maxillary,  37,  39 

Squamo-tympanic,  44 

Sylvius',  184 
Fissures  of  Cerebellum,  206 

of  Cerebrum,  184 

of  Liver,  337 

of  Spinal  Cord,  213 
Flexure,  Sigmoid,  334 
Flocculus,  207 
Fluid.  Cerebro-spinal,  182 
Fold,  Aryteno-epiglottidean,  352 

Glosso-epiglottidean,  353 

Palpebral,  295 

Semilunar,  295 

of  Douglas,  96 
Folium  Cacuminis,  207 
Folliciles,  Hair,  271 

Simple,  332,  335 
Folliculi  Oophori  Vesiculosi,  383 
Fontana's  Spaces,  282 
Fontanelles,  40 
Foot,  56 
Foramen  for  Arnold's  Nerve,  21,  43 

Caecum,  15,  43,  274 

Carotid,  43 

Condylar,  18,  42 

Costo-transverse,  6 

Epiploicum,  326 


Foramen  for  Ethmoidal,  16,  37,  41 
Incisive,  29,  42 
Infraorbital,  28 
Interventricular,  190 
Intervertebral,  5 
for  Jacobson  Nerve,  21,  43 


Jugular,  42 
of  Ke 


[ey  and  Retzius,  211 

Lacerum  Anterius,  25,  36,  41 
Medium,  41 
Posterius,  17,  42 

Magendie's,  182,  211 

Magnum,  17,  42 

Mandibular,  34 

Mastoid,  20,  42 

Mental,  31 

Munro's,  190 

Obturator,  12 

Olfactory,  38,  41 

Ovale,  24,  41 

Optic,  25,  37,  41 

Orbital,  24 

Palatine,  32,  42 

Parietal,  16 

Pterygo-palatine,  42 

Rotundum,  24,  41 

Sacral,  n 

Scarpa's,  29,  42 

Singulare,  311 

Spheno-palatine,  31 

Spinal,  6 

Spinosum,  24,  41 

Stenson's,  29,  42 

Stylo-mastoid,  21,  43 

Supraorbital,  14 

Suprascapular,  45 

Thyroid,  12 

Vertebrale,  6 

Winslow's,  326 
Foramina  at  the  Base  of  the  Skull,  41 

Interventricularia,  190 

Olfactory,  41 

Orbital,  35 

Spheno-maxillary,  42 

Thebesii,  119 

Venarum  Minimarum,  119 
Forearm,  48 

Formatio  Reticularis,  211 
Fornix  Cerebri,  190 

Conjunctivas,  295 
Fossa  of  the  Auricle,  297 

Canine,  28 

Cochlearis  (recessus),  305 

C9ronoid,  48 

Digastric,  20,  34 

Digital  (femoris),  53 
(testis),  374 

Duodenal,  327 

Duodeno-jejunal,  327 

Floccular,  22 

Glenoid,  19 

Hypophyses,  22 

Ileq-colic,  328 

Incisive,  28,  34 

Incudis,  301 

Infraspinous,  45 

Inguinal,  388 

Intercondylar,  55 


4io 


INDEX 


Fossa  of  the  Intersigmoid,  328 

Ischio-rectal,  394 

Jugular,  1 8,  21 

Lacrimal,  15,  36 

Mandibular,  19 

Nasal,  37,  277 

Navicularis  Auriculae,  297 
Penis,  369 
Pudendi,  377 

Olecranon,  48 

Ovalis  Cordis,  108,  119 
Femoralis,  389 

Patellaris,  288 

Pericascal,  328 

Perinaeal,  393 

Peritoneal,  327,  388 

Pterygoid,  25 

Radial,  48 

Rosenmuller's,  322 

Scaphoid,  25 

Spheno-maxillary,  39 

Spheno-palatine,  39 

Sublingual,  34 

Submandibular,  34 

Subscapular,  45 

Supraspinous,  45 

Supra-tonsillaris,  314 

Temporal,  38 

Triangularis  Auriculae,  297 

Trochanteric,  53 

Venae  Cavae  Hepatis,  338 

Vesicae  Felleae,  338 

Zygomatic,  39 
Fossae,  Inguinal,  388 

Nasal,  37,  277 

Perinaeal,  393 

Retro-peritoneal,  327 

of  the  Skull,  41,  42 
Fourchette,  377 
Fovea  Articularis,  6 

Centralis,  285 

Hemispherica,  305 

Inferior  of  4th  Ventricle,  212 

Semi-elliptica,  305 

Superior  of  dth  Ventricle,  212 
Fraenulum  Cerebelli,  207 

Praeputii,  372 
Fraenum  Linguae,  223 
Frenula  Oris,  312 
Frontal  Bone,  14 

Sinuses,  15 
Fundus  Oculi,  285,  286 

Uteri,  380 

Funiculus,      Antero-lateral      of      Cord, 
213 

Cuneatus  of  Medulla,  210 

Gracilis  of  Medulla,  210 

Lateralis  of  Medulla,  209 

Posterior  of  Cord,  213,  215 

Postero-lateral  of  Cord,  214 

Postero-median  of  Cord,  214 

Rolando's,  209 

Teres,  205 

Solitarius,  211,  221 

GALL-BLADDER,  343 
Gartner's  Duct,  383 
Ganglia,  177 


Ganglia,  Basal,  179 

Cervical,  237,  268 

of  the  Cranial  Nerves,  223 

Lumbar,  238,  268 

of  Ninth  Cranial  Nerve,  226 

Pelvic,  238 

Sacral,  268 

Semilunar,  240 

Spinal,  216,  226 

Sympathetic,  268 

of  Tenth  Cranial  Nerve,  226 

Thoracic,  237,  268 

Gangliated   Cord  of  Sympathetic,    237 
Ganglion,  Arnold's,  224 

Bochdalek's,  236 

Cardiac  of  Wrisberg,  239 

Carotid,  236 

Cerebellar,  208 

Ciliary,  224 

Coccygeal,  238,  268 

Cceliac,  240 

Diaphragmatic,  240 

Gasserian,  223 

Geniculate,  225 

Habenulae,  194 

Impar,  236,  268 

Inferius,  226 

Jugular,  226 

Jugulare,  226 

Lenticular,  224 

Meckel's,  224 

Nodosum,  226 

Ophthalmic,  224 

Otic,  224 

Petrous,  226 

Ribes',  236,  237.  268 

of  Root  of  Tenth  Nerve,  226 

Scarpa's,  311 

Semilunar,  223,  240 

Spheno-palatine,  224 

Spinal,  216 

Spirale,  311 

Submandibular,  225 

Submaxillare,  225 

Superius,  226 

of  Trunk  of  the  Tenth    Nerve,    226 

Valentines',  236 

Wrisberg's,  239 
Gasser's  Ganglion,  223 
Genesiology,  i 
Geniculate  Bodies,  193 
Gimbernat's  Ligament,  387 
Gingivae,  317 
Girdle,  Pelvic,  44 

Shoulder,  44 
Gladiolus,  8 
Gland  or  Glands — 

Adrenal,  364 

Aortic  Bodies,  345 

Axillary,  173 

Barth9lin's,  378 

Blandin's,  274 

Bowman's,  279 

Bronchial,  175 

Brunner's,  333 

Bulbp-urethral,  371 

Cardiac,  330 

Carotid  Bodies,  345 


INDEX 


411 


Giands  of  Chromaffin  System,  344 
of  Chromaphil  System,  344 
Ciliary,  293 
Coccygeal,  349 
Cceliac,  174 

of  Cortical  System,  345 
Cowper's,  371 
Ductless,  344 
Duodenal,  333 
Gastric,  329,  330 
Glomus  Caroticum,  345 

Coccygeum,  349 
Ebner's,  274 
Entodermal,  345 
Fundus,  330 
Haemal,  172 

Lymph,  172 
Intestinal,  332,  335 
Kidney,  360 
Lacrimal,  295 
Lien,  275 
Littr6's,  369 
Liver,  336 
Lumbar,  174 
Lymphatic,  171 
Mammary,  383 
Mediastinal,  175 
Meibomian,  294 
Mesenteric,  175 
Moll's,  293 
Mucous,  315 
Nuhn's,  274 
CEsophageal,  323 
Ovary,  382 
Pancreas,  343 
Paraganglia,  345 
Parathyroid,  346 
Parovarium,  383 
Partiod,  315 
Peyer's,  333 
Phaerochrome,  344 
Pineal,  194 
Pituitary,  186 
Prostate,  370 
Pyloric,  330 
Racemose  Serous,  274 
Rosenmuller's,  295 
Salivary,  315 
Sebaceous,  271,  273 
Seminal,  372 
Serous,  274 
Smegma,  372 
Solitary,  333 
Spleen,  375 
Sublingual,  316 
Submandibular,  316 
Submaxillaris,  316 
Sudoriferous,  271,  273 
Supra-renal,  364 
Sweat,  270,  273 
Testicle,  372 
Thymus,  347 
Thyroid.  345 
Tracheal,  355 
Tonsil,  314 
Tyson's,  372 
Urethral,  369,  370 
of  Vascular  System,  348 


Glands,  Vestibulares,  378 
Glans  Clitoridis,  378 

Penis,  372 

Glaserian  Fissure,  19,  43 
Glenoid,  3 

Glisson's  Capsule,  3.36 
Globus  Major  Epididymis,  273 

Minor  Epididymis,  273 
Glomus  Caroticum,  345 

Coccygeum,  349 
Glottis,  353 
Golgi's  Cells,  176,  208 
Gomphosis,  59 
Graafian  Vesicles,  383 
Granulationes  Arachnoideales,  181,  182 
Gray  Matter  (substantia  grisea),  176 
of  Aquaeduct  of  Sylvius,  202 
of  Cerebellum,  208 
of  Cerebrum,  179 
of  Medulla  Oblongata,  209 
of  Pons  Varolii,  204 
of  Spinal  Cord,  215 

Nervous  Tissue,  176 

Rami  Communicantes,  227,  238 
Groove,  Alar,  24 

Auriculo- ventricular,  118 

Bicipital,  47 

Infraorbital,  27 

Intertubercular,  47 

Interventricular,  118 

Lacrimal,  29 

Musculo-spiral,  47 

Mylo-hyoid,  35 

Naso:palatine,  33 

Nervi  Radialis,  47 

Occipital,  20 

Optic,  22 

Pterygo-palatine,  24,  28 
Gubernaculum  Testis,  375 
Gudden's  Commissure,  194,  292 
Gullet,  322 
Gums,  317 
Gyrus,  see  Convolution  or  Lobe 

HABENULAR  Ganglion,  194 

Trigone,  194 
Haemal  Glands,  172 

Lymph  Glands,  172 
Hair  Cells,  Auditory,  310 
Hairs,  273 

Olfactory,  279 
Hamstrings,  112 
Hamular,  3 
Hamulus,  306 
Hand,  50,  105 
Hasner's  Valve,  296 
Haversian  Canals,  4 

Spaces,  4 

System,  4 

Head-plates,  Auditory,  310 
Heart,  118 
Heel,  57 

Helicotrema,  306 
Helix,  297 

Hemispheres,  Cerebral,  183 
Henle's  Loops,  362 
Hensen's  Canal,  307 

Cells.  307 


412 


INDEX 


Hepar,  336 
Hernia,  384 

Femoral,  388 

Coverings  of,  390 

Inguinal,  385 

Coverings  of,  388 
Herophilus'  Torcular,  18 
Hesselbach's  Triangle,  387 
Key's  Ligament,  390 
Hiatus  Canalis  Facialis,  20 

Falk>pii,  20,  42 

Semilunaris,  277 

Highmore  (Nathaniel),  Antrum  of,   27 
Hilton's  Sac,  354 

Hilum  or  Hilus  of  the  Kidney,  360 
of  the  Lung,  358 
of  the  Spleen,  348 
of  the  Supra-renal  Gland,  364 
Hind-brain,  203 
Hip-joint,  68 
Hippocampus  Major  i  191 

Minor,  191 

Horner's  Muscle  (tensor-tarsi),  75 
Houston's  Valves,  335 
Huguier's  Canal,  19,  300 
Humerus,  47 
Humor,  Aqueous,  287 
Hunter's  Canal,  no,  142 
Hyal,  Basi-,  41 

Cerato-,  41 

Stylo-  (styloid  process),  21 

Thyro-,  41 

Tympano-  (vaginal  process),  21 
Hydatid's  of  Morgagni,  373,  382 
Hyoid  Pone,  41 
Hymen,  378 
Hypochondrium,  324 
Hypogastrium,  324 
Hypothalamus,  202 
Hypothenar  Eminence,  106 
Hypophysis  Cerebri,  186 

ILEUM, 331 

Iliac  Regions,  324 

Ilium,  13 

Incisura  Acetabuli,  12 

Cerebelli,  206 

Intertragica,  297 

Marsupialis,  206 

Radialis,  49 

Rivini,  298 

Semilunaris,  49 

Thyroidea,  350 
Incus,  301 

Infundibula  of  the  Kidney,  361 
Infundibulum,  26,  277 

Cerebri,  186 

Cochleas,  306 

Nasal,  277 

Tubae,  Uterinae,  382 
Inguinal  Regions,  324,  385 
Insula  Cerebri,  183 
Inter-brain,  192 
Interspaces,  Perinatal,  393 
Intestine,  Large,  333 

Small,  330 
Intestinum  Crassum,  333 

Tenue,  330 


Intumescentia  Ganglioformis,  225 
Iris,  284 

Ischio-pubic  Ramus,  12 
Ischio-rectal  Fossa,  394 

Anterior  Extension  of,  394 

Region,  394 

Space    394 
Ischmm,  13 
Island  of  Reil,  183 
Isthmus  Cerebri,  194 

of  Fallopian  Tube,  382 

Faucium,  314 

of  Hind-brain,  203 

Rhombenecephali,  178,  203 

of  Thyroid  Gland,  345 

Tubas  Auditivae,  303 

Uterinae,  382 

Iter  Chordae  Anterius,  19,  300 
Posterius,  300 

a  Tertio  ad  Quartum  Ventriculum, 

202 
Ivory,  318 

JACOB'S  Membrane,  287 
Jacobson's  Nerve,  221,  250,  303 

Organ,  278 
Joint,  see  Articulations 

Ankle,  71 

Elbow,  66 

Hip,  68 

Rotators  of  the  Hip- joint,  112 

Knee,  69 

Shoulder,  65 

Wrist,  67 
Joints,  Motion  in,  60 

Structure  of,  60 
Jugular,  Foramen,  42 

Fossa,  1 8,  21 

Ganglia,  226 

Process,  18 

Surface,  21 

Vein,  165 

KNEE-JOINT,  69 
Kidney,  360 
Kirkring's  Valves,  332 
Krause's  End-bulbs,  177.  272 

LABI  A  Oris,  312 

Pudendi  Majora,  377 

Minora,  377 
Labium  Tympanicum,  309 

Vestibulare,  309 
Labyrinth,  304 

Membranous,  304,  307 

Osseous,  304,  305 
Lacertus  Fibrosus,  133 
Lachrymal,  see  Lacrimal 
Lacrimal  Apparatus,  295 

Bone,  29 

Canaliculi,  295 

Canals,  295 

Carunci,  295 

Fossa,  15,  36 

Glands,  300 

Groove,  24 

Nerve,  218,  246 

Papilla,  294 


INDEX 


413 


Lacrimal  Punctum,  294 

Sac,  296 

Lacteals,  171,  332 
Lacuna  Magna  Urethrae,  369 
Lacunae,  4 

Lacus  Lacrimalis,  293 
Lamina  Basilaris,  309 

Chorio-capillaris,  283 

Cinerea,  186 

Cribrosa  Auris,  311 
Scleraj,  281 

Elastica,  282 

Pusca,  281 

Papyracea,  26 

Reticularis,  310 

Spiralis,  306 

Superchoroidea,  283 

Terminalis,  186 

Vasculosa,  283 
Laminae,  5 

Lancisi's  Nerves,  190 
Larynx,  350 
Layer,  Basilar  (skin),  270 

Ganglionic  (retinal),  286 

Granular  (cerebellar),  209 

Molecular  (cerebellar),  209 
(retinal),  286 

Nuclear  (retinal),  286 

Papillary  (skin),  271 

Pigmentary  (retinal),  287 

of  Rods  and  Cones  (retinal),  286 

Rust-colored  (cerebellar),  208 

Turner's  (cerebellar),  208 
Leg,  54 
Lemniscus,  Lateral,  199 

Medial,  198 
Lens,  Crystalline,  288 
Lieberkuhn's  Crypts,  332 
Ligament,  60 
Ligament  or  Ligaments — 

Acromio-clavicular,  65 

Alar,  71 

of  Ankle-joint,  72 

Annular,  Anterior,  105 
Posterior,  105 

Anterior  Common,  61 

Arcuate,  107 

Astragalo-navicular,  72 

Atlanto-axial,  61 

Atlo-axoid,  61 

of  the  Bladder,  366 

Broad  of  Liver,  338 
of  'Uterus,  381 

Burns',  390 

Calcaneo-astragaloid,  72 

Calcaneo-cuboid,  72 

Calcaneo-navicular,  72 

Capsular,  see  Individual  Joints 

Carpo-metacarpal,  68 

of  Carpus,  67 

Check,  62,  80 

Chondro-sternal,  63 

Chondro-xyphoid,  63 

Coccygeal,  63 

Conoid,  65 

Coraco-acromial,  65 

Coraco-clavicular,  65 

Coraco-humeral,  65 


Ligaments,  Coronal,  71 
Coronary,  71,  327 
Costo-clavicular,  65 
Costo-central,  62 
Costo-transverse,  63 
Costo-yertebral,  62 
Cotyloid,  69 
Crico-arytenoid,  353 
Crico-thyroid  Capsular,  353 
Crico-tracheal,  353 
Crucial,  70 
Cruciform,  62 
Deltoid,  72 
Dentate,  213 

Dorsal,  see  Individual  Joints 
of  Elbow- joint,  66 
of  Eye,  280 
Falciform,  64,  339 
of  Fingers,  68 
of  Foot,  72 
Gimbernat's.  387 
Glenoid,  65 
Glosso-epiglottic,  353 
of  Hand,  68 
Key's,  390 
of  Hip-joint,  69 
Hyo-epiglottic,  352 
Ilio-femoral,  69 
Ilio-lumbar,  63 
Ilio-pectineal,  107 
of  Incus,  302 
Inguinal,  387 
Interarticular,  62 
Interchondral,  63 
Interclavicular,  65 
Interosseous,  see  Individual  Joints 
Interspinous,  61 
Intertransverse,  61 
Intervertebral,  61 
Ischio-fempral,  69 
of  Knee-joint,  69 
of  Larynx,  352 
of  Larynx,  352 

Lateral,  see  Individual  Joints 
Lieno-renal,  348 
of  Liver,  338 
Lockwood's,  76,  281 
Lumbo-sacral,  63 
of  the  Lung,  356 
of  Malleus,  302 
Metacarpal,  68 
Metacarpo-phalangeal,  68 
Metatarsal,  73 
Metatarso-phalangeal,  73 
Nuchal.  6 1,  88 
Occipito-atlantal,  62 
Occipito-axial,  62 
Occipito-odontoid,  62 
of  the  Odontoid  Process,  62 
Orbicular  of  Radius,  66 
of  the  Ossicles,  302 
of  the  Ovary,  383 
Palpebral,  294 
Patellar,  69 
Pectineo-femoral,  69 
Peritoneal,  326,  327 
Phreno-colic,  335 
Plantar,  72 


4i4 


INDEX 


Ligaments,  Posterior  Common,  61 
Poupart's,  108,  387 
Pterygo-mandibular,  78 
Pubic,  64 

Pubo-prostatic,  366 
Pubo-vesical,  366 
Radio-carpal,  67 
Radio-ulnar,  67 
Recto- vaginal,  381 
Rhomboid,  65 
Round  of  Hip- joint,  69 

of  Liver,  339 

of  Uterus,  381 
Sacro-C9ccygeal,  64 
Sacro-iliac,  64 
Sacro-sciatic,  64 
Sacro-spinous,  64 
Sacro-tuberous,  64 
Sacro-uterine,  381 
of  the  Scapula,  65 
of  Shoulder,  65 
Spiral  of  Cochlea,  309 
or  Spleen,  348 
Spleno- phrenic,  348 
Spheno-mandibular,  65 
of  Stapes,  302 
Stellate,  62 
Sterno-clavicular,  65 
of  the  Sternum,  63 
Stylo-hyoid,  21,  41 
Stylo-mandibular,  61 
Subpubic,  64 
Supra-pubic,  64 
Supra-spinous,  61 
Suspensory  of  Bladder,  366 

of  Eye,  281 

of  Incus,  302 

of  Lens,  288,  289 

of  Liver,  339 

of  Odontoid,  62 

of  Ovary,  383 

of  Penis,  393 

of  Spleen,  348 
Tarsal  of  Eye,  294 
Temporo-mandibular,  60 
Thyro-arytenoid,  353 
Thyro-epiglottic,  353 
Thyro-hyoid,  353 
Tibio-fibular,  71 
Transverse  of  Atlas,  61 

Cotyloid,  69 

of  Knee,  71 

of  Scapula,  46 
Trapezoid,  65 
Triangular,  393 
Ulno-carpal,  67 
Utero-sacral,  381 
Utero-vesical,  381 
of  the  Uterus,  381 
of  Vertebrae,  61 
of  Winslow,  70 
of  Wrisberg,  71 
Y-ligament,  69 
of  Zinn,  76 

Ligamentum  or  Ligamenta — 
Alaria,  71 
Arcuata,  107 
Calcaneo-fibulare,  72 


Ligamenta,  Calcaneo-tibiale,  72 
Carpi  Dorsale,  105 

Transversum,  105 
Collaterale,  Fibulare,  70 

Radiale,  66 

Tibiale,  70 

Ulnare,  66 

Coronaria  Hepatis,  327,  339 
Cruciata  Cruris,  115 
Denticulatum,  213 
Falciforme  Hepatis,  339 
Gastro-lienale,  326 
Hepato-gastricum,  326 
Hyo-thyreoidea,  353 
Inguinale,  387 

Reflexum,  387 
Laciniatum,  115 
Lacunare,  387 
Lata  Uteri,  381 
Latum  Pulmonis,  356 
Lieno-renale,  327 
Mucosum,  71 
Nuchae,  61,  88 
Patellae,  69 

Pectinatum  Iridis,  285 
Peronaei  Retinaculum,  115 
Sacro-spinosum,  64 
Sacro-tuberosum,  64 
Spirale  Cochleae,  309 
Suspensorium  Dentis,  62 
Talo-fibulare,  72 
Teres  Femoris,  69 

Hepatis,  339 

Umbilicale,  365 

Uteri,  381 

Thyreo-epiglotticum,  353 
Transversum  Cruris,  115 
Triangulare  Hepatis,  339 
Light  Spot,  298 
Limbus  Fossae  Ovalis,  119 
Laminae  Spiralis,  309 
Line,  Inter-trochanteric,  53 

Popliteal,  ss 
Linea  Aspera,  53 

Ilio-pectinea,  14 

Quadrati  (inter-trochanteric  ridge), 

Lines,  Schreger's,  319 

Lingua,  273 

Lingula  Cerebelli,  203 

Lips,  312 

Liquor  Morgagni,  289 

Lithotomy,  Structures  Concerned,  396 

Littr6's  Glands,  369 

Liver,  336 

Structure  of,  339 
Lobe  of  the  Ear,  297 
Lobes  and  Gyri  of  the  Brain — 

Ala  Lobuli  Centralis,  207 

Amygdala,  207 

Angular,  185 

Biventral,  207 

Broca's,  185 

Buccal,  188 

Centralis,  Anterior,  185 
Posterior,  185 

Clivus  Monticuli,  207 

Commissura  Simplex,  207 


INDEX 


415 


Lobes,  Cresenctic,  207 

Culmen  Monticuli,  207 

Cuneus,  186 

Dentate,  191 

Diclive,  207 

Flocculus,  207 

Folium  Cacuminis,  207 

Fraenulum,  207 

Frontal,  185 

Fusiformis,  186 

Glandular,  188 

Gracile,  207 

Hippocampal,  186 

Limbic,  183 

Lingualis,  186 

Lingula,  207 

Lobulus  Centralis,  207 

Occipital,  186 

Occipito-temporal,  186 

Olfactory,  183 

Operti,  1 86 

Orbital,  185 

Parietal,  185 

Postcentral,  186 

Postparietal,  185 

Precentral,  186 

Precuneus,  185 

Pyramid,  207 

Semilunar,  207 

Slender,  207 

Subcalcarine,  186 

Supramarginal,  185 

Temporal,  183,  186 

Tonsil,  207 

Tuber  Valvulae,  207 

Uncinate,  186 

Uvula,  207 

Vermis,  206,  207 

Vinculum  Lingulae,  207 

Worm,  206,  207 
Lobes  of  the  Cerebellum,  207 

of  the  Cerebrum,  183 

of  the  Liver,  338 

of  the  Prostate  Gland,  370 

of  the  Thyroid  Gland,  345 
Lobule  of  the  Ear,  297 
Lobules  of  Liver,  340 

of  the  Lung,  359 

of  the  Mammary  Gland,  384 
Lobus  Caudatus,  338 

Quadratus,  338 

Spigelii,  338 

Lockwood's  Ligament,  76 
Locus  Caeruleus.  20 a,  212 

Perforatus,  186 
Loops  of  Henle,  362 
Lower's  Tubercle,  120 
Lumbar  Regions,  324 
Lumbo-dorsal  Fascia,  90 
Lungs,  357 
Lunula,  273 
Lymphatic  System,  171 

Vessels,  171 
Lymph  Glands,  171 
Haemal,  172 

Space,  Peri-choroidal,  283 
Peri-sclerotic,  281 

Spaces  of  Eye,  290 


Lymphatics  of  the — 

Abdomen,  174 

Auricular  Region,  173 

Bladder,  368 

Bronchi,  175,  356 

Buccal  Region,  173 

Cardiac  Region,  175 

Cervical  Region,  173 

Head,  172 

Inguinal  Region,  174 

Intestine,  333,  336 

Larynx,  354 

Liver,  341 

Lower  Extremity,  174 

Lung,  359 

Kidney,  363 

Mammary  Gland,  384 

Mastoid  Region,  173 

Mediastinum,  175 

Mesentery,  175 

Neck,  172,  173 

Pancreas,  344 

Parotid  Regi9n,  173 

Pectoral  Region,  174 

Pelvis,  174 

Occipital  Region,  172 

Spleen,  349 

Submandibular  Region,  173 

Supra-renal  Gland,  365 

Testicle,  375 

Thymus  Gland,  347 

Thyroid  Gland,  346 

Tongue,  275 

Trachea,  356 

Upper  Extremity,  173 

Uterus,  382 

Vagina,  379 
Lympho-glandulae,  171 

Auriculares,  173 

Bronchiales,  175,  356 

Ceryicales,  173 

Cubitales,  173 

Linguales,  173 

Mesentericae,  175 

Occipitales,  172 

Parotidae,  173 

Submaxillares,  173 
Lyra,  190 

MACULA  Acustica,  307 

Lutea,  285 

Saccularis,  308 

Utricularis,  308 
Malar  Bone,  30 
Malleolus,  55.  56 
Malleus,  301 
Malpighi's  Bodies,  349,  361 

Pyramids,  361 
Malpighian  Tufts,  361 
Mammary  Gland,  383 
Mandible,  33 
Manubrium  of  Malleus,  301 

of  Sternum,  8 
Marrow  of  Bones,  4 
Massa  Intermedia,  193 
Masses,  Lateral  of  Ethmoid,  26 
Mastoid,  3 

Cells,  20 


4i6 


INDEX 


Mastoid,  Foramen,  20 

Process,  20 
Matrix  of  Nail,  273 
Maxilla,  27 

Meatus  Acusticus  Externus,  297 
Interims,  311 

Auditorius  Externus,  20,  297 
Internus,  20,  42,  311 

Nasi,  3.8,  277 

Urinarius,  369,  370 
Meckel's  Diverticulum,  331 

Ganglion,  224 

Media,  Refracting  of  Eye,  287 
Mediastinum  Testis,  374 

Thoracis,  356 
Medulla  Oblongata,  208 

Spinalis,  213 
Membrana  Basilaris,  309 

Crico-thyroidea,  353 

Granulosa,  383 

Limitans  Externa,  287 
Interna,  286 

Nictitans,  295 

Pupillaris,  285 

Sacciformis,  67 

Tectoria,  309 

Tympani,  298 

Secundaria,  300 
Membrane  or  Membranes — 

Brain,  180 

Bruch's,  283 

Demour's,  282 

Descemet's,  282 

Hyaloid,  288 

Hyo-glossal,  274 

Hyo-thyroid,  353 

Interosseous,  67,  71 

Jacob's,  287 

Limiting,  286,  287  . 

Meningeal,  180,  213 

Mucous,  271 

Nasmyth's,  319 

Obturator,  12 

Pituitary,  278 

Reissner's,  309 

Schneiderian,  278 

Shrapnell's,  298 

of  Spinal  Cord,  213 

Synovial,  60 
Carpal,  67 
Tarsal,  72 

Thyro-hyoid,  353 

Thyroid,  12 

Vestibular,  309 
Meninges  of  Brain,  180 

of  Spinal  Cord,  213 
Menisci  of  Knee-joint,  70 
Mesenteries,  327 
Mesencephalon,  178,  203 
Mesencephalic  Root  of  Fifth  Nerve, 
Meso-colon,  327,  334 
Meso-rectum,  327 
Meso-sigmoid,  327 
Metacarpus,  51 
Metapore,  182,  211 
Metatarsus,  58 
Metathalamus,  193 
Metencephalon,  178,  203 


Meynert's  Commissure,  292 
Mid-brain,  178,  194 
Modiolus  Cochleae,  306 
Moll's  Glands,  293 
Mons  Veneris,  377 
Morgagni's  Hydatids,  373,  382 
Lacuna,  360 
Sinus,  359 
Mouth,  312 
Miiller's  Fibres,  286 
Munro's  Foramen,  190 
Muscle  or  Muscles,  73 
Abdominal,  95 
Abductor  Digiti  Quinti  (hand),  106 

.(foot),  116 
Indicis  (ist  dorsal  interosseous), 

107 
Minimi  Digiti  (foot),  116 

Digiti  (hand),  106 
Pollicis,  106 
Brevis,  106 
Longus,  105 
Accelerator  Urinae,  98 
Accessories    ad     Ilio-costalem,    91 
of  Acromial  Region,  100 
Adductor  Brevis  (femoris),  no 
Longus  (femoris),  no 
Magnus  (femoris),  no 
Obliquus  Hallucis,  117 

Ppllicis,  106 
Pollicis,  106 
Transyersus  Hallucis,  117 

Pollicis,  106 
Ancpneus,  104 
Anti-tragicus,  80,  297 
Appendicular,  86,  87 
of  Arm,  100 
Articularis  Genu,  109 
Aryteno-epiglottideus    Inferior,    86 

Superior,  86 
Arytenoideus,  86 
Attollens  Auriculam,  75 
Attrahens  Auriculam,  75 
of  Auricle,  297 
Auricularis  Anterior,  75 
Posterior,  75 
Superior,  75 


Axial.  87 

ygos  UT 
of  Back,  86 


Azygos  Uvulae,  84 


Biceps,  ip  i 

Femoris,  112 

Flexor  Cubiti,  101 
Biventer  Cervicis,  92 
of  the  Bladder,  367 
Bowman's  (ciliary),  284 

(Cochlear),  309 
Brachialis,  101 

Anticus,  loi 
Brachio-radialis,  104 
of  Buccal  Region,  78 
Buccinator,  78 
Bulbocavernosus,  98 
Caninus,  77 

of  Cervical  Region,  80,  84 
Cervicalis  Ascendens,  91 
Chondro-glossus,  81 
Ciliary,  284 


INDEX 


417 


Muscles,  Circumflexus  (tensor)  Palati,  83 
Coccygeus,  98 
Complexus,  92 

Compressor  Narium  Minor,  77 
Nasi,  77 
Sacculi  Laryngis  of  Hilton  (ary- 

teno-epiglottideus  inf.),  86 
Urethrae  (female),  99 

(male),  98 
Constrictor  Isthmi  Paucium,  84 


Pharyngis  In 
Middle,  83 


is  Inferior,  83 


Superior,  83 
Coraco-brachialis,  101 
of  Cranial  Region,  75 
Corrugator  Cutis  Ani,  97 

Supercilii,  75 
Cremaster,  95 
Crico-arytenoid,  Lateral,  86 

Posterior,  85 

Crico-thyroid  (thyreoideus),  85 
Crureus,  109 

Cursor  Ani  (latissimus  dorsi),  88 
Deltoid  (deltpideus),  100 
Depressor  Ali  Nasi,  77 

Anguli  Oris,  78 

Labii  Inferioris,  78 

Septi  Nasi,  77 
Detrusor    Urinse    (outer    muscular 

coat  of  the  bladder),  367 
Diaphragm,  94 
Digastric,  82 

Dilator  Naris  Anterior,  77 
Posterior,  77 

Pupillae,  285 

Tubae  Auditivae,  303 
of  Dorsal  Region,  86 
of  the  Ear,  75.  79,  297 
Ejaculator  Seminis  (bulbo-caverno- 
sus),  98 

U  rinse  (bulbo-cavernosus),  98 
of  the  Epiglottis,  85,  354 
Erector    Clitoridis    (ischio-caverno- 
sus),  09 

Penis  (ischio-cavernosus),  99 

SpinEB,  90 

of  the  Eustachian  Tube,  303 
of  Expression,  77,  79 
Extensor  Brevis  Digitorum,  115 
Pollicis,  1  05 

Carpi  Radialis  Brevoir,  104 

Longior,  104 
Ulnaris,  104 

Coccygis,  93 

Communis  Digitorum,  104 

Digiti  Quinti  Proprius,  104 

Hallucis  Longus,  113 

Indicis,  105 

Longus  Digitorum,  113 
Hallucis,  113 
Pollicis,  ip$ 

Minimi  Digiti,  104 

Ossis  Metacarpi  Pollicis,  105 
Extensor,  Primi  Internodii  Pollicis, 
105 

Proprius  Hallucis,  113 

Secundi  Internodii  Pollicis,  105 
External  Oblioue  (abdomen),  95 


Muscles  of  Eyeball,  76,  289 
of  Eyelid,  75,  294 
of  the  Face,  77,  79 
of  the  Femoral  Region,  108,  no,  112 
of  the  Fibular  Region,  115 
Flexor  Accessorius,  116 
Brevis  Digitorum,  116 
Hallucis,  117 
Minimi  Digiti  (foot),  117 

(hand),  106 
Pollicis,  106 
Carpi  Radialis,  102 

Ulnaris,  103 
Digiti  Quinti  Brevis   (foot),   117 

(hand),  106 
Digitorum  Brevis,  106 
Hallucis  Brevis,  117 
Longus  Digitorum,  114 
Hallucis,  114 
Pollicis,  103 
Ossis    Metacarpi   Pollicis    (oppo- 

nens),  106 
Pollicis  Brevis,  106 

Longus,  103 

Profundus  Digitorum,  103 
Sublimis  Digitorum,  103 
of  the  Forearm,  102 
of  the  Foot,  115 
Frontalis,  75 
Gastrocnemius,  113 
Gamellus  Inferior,  in 

Superior,  in 
Genio-glossus,  82 
Genio-hyo-glossus,  82 
Genio-hyoid,  82 
Glosso-palatinus,  84 
of  the  Gluteal  Region,  no 
Glutaeus  or  Gluteus  Maximus,  no 
Medius,  no 
Minimus,  ill 
Gracilis,  109 
Hamstring,  112 
of  the  Hand,  106 
of  the  Head,  75 
Helicis  Major,  79,  297 

Minor,  80,  297 

Hilton's    (aryteno-epiglottideus  in- 
ferior), 86 
of  the  Hip,  1 10 
Hip  Rotators,  112 
Homer's  (tensor  tarsi),  75 
of  Humeral  Region,  101 
Hyo-glossus,  82 
Hyppthenar,  106 
of  Iliac  Region,  107,  no 
Iliacus,  108 
Ilio-capsularis      (outer      fibres      of 

iliacus),  108 
Ilio-coccygeus    (posterior   fibres   of 

levator  ani),  98 
Ilio-costales,  91 

Lumborum,  91 
Infra-cost  ales,  94 
Infra-hyoid  Region,  81 
Infraspinatus,  101 
Intercostal,  External,  93 

Internal,  93 
Internal  Oblique  (abdomen),  95 


4*8 


INDEX 


Muscles,  Interossei  of  foot,  117 
Inter-spinales,  93 
Inter-transversaTes,  92 
Iritertransversarii,  93 
Involuntary,  74 
Ischio-cavernosus,  98,  99 
of  Ischio-rectal  Region,  97,  395 
Kerato-cricoideus,  85 
Labial  Region,  77 
of  Larynx,  85,  354 
Latissimus  Dorsi,  88 
Laxator  Tympani,  80 
of  the  Leg,  112 
Levator  Anguli  Oris,  78 
Scapulae,  88 

Ani,  98 

Glandulae  Thyroideae,  346 

Labii  Superioris,  77 
Alasque  Nasi,  77 

Menti,  78 

Palati,  83 

Palpebrae  Superioris,  76 

Prostatae      (pre-anal      fibres      of 
levator  am),  98 

Scapulae,  88 

Urethrae      (pre-anal      fibres      of 
levator  ani),  98 

Veli  Palatini,  83 
Levatores  Costarum,  94 
Lingualis,  83 
Lingual,  Longitudinal,  83 

Transverse,  83 

Vertical,  83 
of  Lingual  Region,  82 
Longitudinalis  Linguae  Inferior,  83 

Superior,  83 
Longissimus  Capitis,  91 

Cervicis,  91 

Dorsi,  91 
Longus  Capitis,  84 

Colli,  84 

of  Lower  Extremity,  107 
Lumbricales  of  foot,  116 

of  hand,  107 
Mandibular  Region,  78 
Masseter,  79 
of  Mastication,  79 
of  Maxillary  Region,  77 
Mentalis,  78 
Multifidus,  92 

Spinae,  92 
Mylo-hyoid,  82 
Nasalis,  77 
of  Nasal  Region,  77 
Naso-labialis    (upper  medial   fibres 

of  orbiculans  oris),  78 
of  Neck,  80 

Obliquus  Abdominis  Externus,  95 
Internus,  95 

Auriculae,  80,  297 

Capitis  Inferior,  93 
Superior,  93 

Oculi  Inferior,  77 
Obliquus  Oculi,  Superior,  76 
Obturator  Externus,  112 

Internus,  112 
Occipitals,  75 
Occipito-frontalis,  75 


Muscles,  Omo-hyoid,  81 

Opponens  Digiti  Quinti,  107 

Minimi  Digiti,  107 

Ppllicis,  106 
Orbicularis  Oculi,  75 

Oris,  78 

Palpebrarum,  75 
of  Orbital  Region,  76,  289 
of  Palatal  Region,  83,  313 
Palato-glossus,  8j 
Palato-pharyngeus,  84 
of  Palmar  Region,  106 
Palmaris  Brevis,  106 

Longus,  102 
of  Palpebral  Region,  75 
Fectineus,  no 
of  Pectoral  Region,  99 
Pectoralis  Major,  99 

Minor,  99 

of  Pelvic  Outlet,  97 
Perforans,  103 
Perforatus,  103 
of  Perinaeum,  female,  99,  396 

Male,  98,  393 
of  Peroneal  Region,  115 
Peroneus  (peronasus)  Brevis,  115 

Longus,  115 

Tertius,  113 

of  Pharyngeal  Region,  83,  322 
Pharyngo-glossus      (superior     con- 
strictor), 83 
Pharyngo-palatinus,  84 
of  Pinna,  79 
of  Plantar  Region,  116 
Plantaris,  114 
Platysma-myoides,  80 
Popliteus,  114 

Prevertebral  of  Head  and  Neck,  84 
Procerus,  77 
Pronator  Quadratus,  103 

Radii  Teres,  102 

Teres,  102 
Psoas  Magnus,  107 

Major,  107 

Minor,  108 

Parvus,  108 

of  Pterygo-mandibular  Region,   79 
Pterygoid,  External,  79 

Internal,  79 
Pubo-coccygeus    (medial    fibres    of 

levator  ani),  98 
Pyrarnidalis,  97 

Nasi,  77 
Pyraformis,  in 
Quadratus  FenKms,  112 

Labii  Inferioris,  78 
Superioris,  78 

Lumborum,  97 

Menti,  78 

Plantae,  116 
Quadriceps  Extensor,  108 

Femons,  108 
Radial  Region,  102 
Recti  Oculi,  76 
Recto-urethralis      (pre-anal     fibres 

of  levator  ani),  98 
Recto-uterinus   (sacro-uterine  liga- 
ment), 381 


INDEX 


419 


Muscles,  Rectus  Abdominis,  96 

Capitis  Anticus  Major,  84 

Minor,  84 
Lateralis,  84,  93 
Posticus  Major,  93 
Minor,  93 

Femoris,  109 

Oculi  Externus,  76 
Inferioris,  76 
Internus,  76 
Lateralis,  76 
Medialis,  76 
Superioris,  76 
Retrahens  Auriculam,  75 
Rhomboideus  Major,  89 

Minor,  88 
Risorius,  79 
Rotatores,  92 

Spinse,  92 

Rotators  of  the  Hip,  no 
Sacro-lumbalis,  91 
Sacro-spinalis,  90 
Salpingo-pharyngeus,  84 
Santorini's  (risorius),  79 
Sartorius,  108 
Scalenus  Anticus  (anterior),  85 

Medius,  85 

Posticus  (posterior),  85 
of  the  Scalp,  75 
of  Scapular  Region,  100 
Semi-membranosus,  112 
Semi-spinalis  Capitis,  92 

Cervicis,  92 

Colli,  92 

Dorsi,  92 
Serratus,  Anterior,  100 

Magnus,  100 

Posticus  (posterior)  Inferior,  90 

Superior,  89 
of  the  Shoulder,  100 
Skeletal  (voluntary),  73,  74 
Sphincter  Ani  Externus,  97 
Internus,  97 
Tertius,  97 

Pupillae,  285 

Vaginae,  99 

Vesicae,  367 
Spinalis  Cervicis,  92 

Colli,  92 

Dorsi,  92 
Splenius  Capitis,  90 

Cervicis,  90 

Colli,  90 

Stapedius,  80,  302 
Striated  Muscle,  73,  74 
Striped  Muscle,  73,  74 
Structure  of  Muscle,  73 
Stylo-glossus,  82 
Stylo-hyoid,  82 
Stylo-pharyngeus   83 
Sub-anconeuc,  102 
Subclavius,  100 
Subcrureus,  109 
of  Suboccipital  Region,  93 
Subscapularis,  100 
Supinator,  105 

Brevis,  105 

Longus,  104 


Muscles  of  Supra-hyoid  Region,  82 
Supraspinatus,  101 
Temporal,  79 

of  Temporo-mandibular  Region,  79 
Tensor  Fasciae  Femoris,  108 
Latae,  108 

Palati,  83 

Tarsi,  75 

Tympani,  80,  302 

Vaginae  Femoris,  io3 

Veli  Palatini,  83 
Teres  Major,  101 

Minor,  101 
Thenar,  106 
of  Thigh,  108 
of  Thorax,  93,  99 
Thyro-(thyreo)  Arytenoideus,  86 
Thyro-(thyreo)  Epiglottideus,  86 
Thyro-(thyreo)  Hyoid,  81 
Tibialis  Anticus  (anterior),  112 

Posticus  (posterior),  114 
of  Tibio-fibular  Region,  112 
Todd's  (cochlear),  309 
of  the  Tongue,  Extrinsic,  82,  274 

Intrinsic,  83,  275 
Trachelo-Mastoid,  91 
Tragicus,  80,  297 
Transversalis  Abdominis,  96 

Cervicis,  91 

Colli,  91 
Transversus  Auriculae,  80,  297 

Linguae,  83 

Pennaei  Profundus,  98,  99 

Superficialis,  98,  99 
Trapezitts,  88 
Triangularis  Menti,  78 

Sterni,  94 
Triceps,  102 

Extensor  Cubitis,  102 
Triticeo-glossus,  86 
of  the  Trunk,  86 
Turner's  (Kerato-cricoideus),  85 
of  Tympanum,  80,  302 
of  Ulnar  Region,  102 
Unstriated  Muscle,  73,  74 
Unstriped  Muscle,  73.  74 
of  Upper  Extremity,  99 
Urethral,  369 
Uvulae,  84 
Vastus  Externus,  109 

Intermedius,  109 

Internus,  109 

Lateralis,  109 

Medialis,  109 
Vertical  is  Linguae,  83 
Voluntary  Muscle,  73,  74 
Zypomaticus,  78 

Major,  78 

Minor,  78 
Muscular  Fibre,  73 
Musculi  Papillares,  120,  122 
Myencephalon,  177.  208 
Myelology, 

NAILS,  272 
Nares,  276 
Nasal  Bones,  27 

Conchae,  26,  32 

Fossa,  277 


420 


INDEX 


Nasal  Meatus,  26,  277 

Septum,  276 

Nasmyth's  Membrane,  319 
Naso-labial  Band,  78 
Nasopharynx,  321 
Nates,  202 
Navel,  298 
Navicular  Bone,  57 
Neck  of  the  Bladder,  366 

of  the  Femur,  52 

of  the  Humerus,  47 

Surgical  Triangles  of,  128 

of  the  Uterus,  398 
Nerve  or  Nerves — 

Abducent,  219,  252 

Accessorius,  222,  250 

Acustic,  220,  310 

Alveolar,  219,  246 

Anastomoticus  Tibialis,  235,  236 

of  Ankle-joint,  235 

of  the  Arm,  229 

Arnold's,  221,  250 

Auditory,  220,  310 

of  Auditory  Canal,  219,  246 

of  Auricle,  298 

Auricular,  Anterior,  219,  246 
Great,  227,  254 
from  Pneumogastric,  221,  250 
Posterior,  220,  248 

Auricularis  Magnus,  227 

Axillaris,  229 

Bell's,  229 

of  Bladder,  368 

of  Bronchi,  356 

Buccal,  of  Facial,  220,  248 


Long,  219 

of  ME 


[andibular,  219,  246 
Buccinator,  219,  246 
Calcaneal,  Lateral,  235,  267 

Medial,  235,  267 
Calcaneo-plantar,  235,  267 
Canalis  Pterygoidei,  226 
Cardiac,  119 

Cervical,  222,  237,  250,  268 

Inferipr,  222 

Superior,  222,  237,  268 

Thoracic,  222,  250 
Carotico-tympanic,  237 
Carotid,  221 
Cavernus,  242 
Cells,  176 
Cerebral,  216 
Cervical,  220,  227 
Cervico-facial,  220,  248 
Chorda  Tympani,  220,  248,  276 
Ciliary,  Long,  218,  246 

Short,  224 
Circumflex,  229,  260 
Clunium  Inferioris  Medialis,  234 
Coccygeal,  233,  262 
Cochlear,  221,  252,  311 
Communicantes,  Gray  Rami,  227 

Fibular,  236 

Hypoglossi,  228,  254  * 

Peronei,  236,  267 

Tibial,  235,  267 

'White  Rami,  227,  238 
Cranial,  216 


Nerves,  Crural,  Anterior,  233,  264 

Genito-,  232,  264 
Cutaneous,  Abdominal,  231 
Antibrachii  Medialis,  229 

Posterior,  229 
Brachii  Medialis,  229 

Posterior,  230 
C9lli,  227 
Digitales  Plantares,  235 

Volares,  229 
Dorsal,  230 

Antibrachial,  229 
Femoral,  234 

External  Femoral,  232,  264 
Internal,  229,  256 

Femoral,  233 
Lateral  Brachial,  229 

Femoral,  232 
Lesser  Internal.  229,  256 
Medial  Antibrachial,  229 
Brachial,  229 
Femoral,  233,  264 
Palmar,  229 
Perforating  234,  266 
Plantar,  Lateral,  235 

Medial,  236 
Posterior  Antibrachial,  229 

Femoral,  234 
Surae  Lateralis,  236 

Medialis,  235 

Dental,  Anterior  Superior,  219,  246 
Inferior,  219,  246 
Middle  Superior,  219,  246 
Posterior  Superior,  219,  246 
Descendens  Hypoglossi,  222,  252 
Digastric  of  Facial,  220,  248 

of  Mylo-hyoid,  219,  246 
Digital  (foot),  235 

(hand),  229 
Digitales  Plantares,  235 

Volares,  229 
Dorsal  of  Clitoris,  234,  266 

of  Penis,  234,  266 

of  the  Ear,  see  Individual  Portions 
Eighth  Cranial,  220,  252,  311 
of  Elbow-joint,  230 
Eleventh  Cranial,  222,  250 
of   Equilibration   (vestibular),    221, 

252,  319 
Endings,  177 
of  Eustachian  Tube,  304 
of  Eyeball,  218,  219,  289 
of  Eyelids,  218,  219,  289 
Eye-muscles,  218,  219,  289 
Facial,  220,  248 
Femoral,  233 
Fibres,  177 

Fifth  Cranial,  218,  2^6 
First  Cranial,  216,  244 
Fourth  Cranial,  217,  244 
Frontal,  218,  246 
Gastric,  222 
Genital,  232,  264 
Genito-crural,  232,  264 
Genito-femoral,  232,  264 
Glosso-palatine,  220,  248,  310 
Glosso-pharyngeal,  221,  250 
Gluteal,  Inferior,  234,  266 


INDEX 


421 


Nerves,  Gluteal,  Superior,  234,  266 
Gustatory,  219,  246 
Haemorrhoidal,  234,  266 
of  Heart,  119 
Hepatic,  340 
of  Hip-joint,  234 
Hypo-glossal,  222,  252 
Ilio-hypqgastric,  232,  264 
Ilio-inguinal,  232,  264 
Incisive,  219,  246 
Infra-orbital,  218,  220,  246 
Infra-trochlear,  218,  246 
Intercostal,  Abdominal,  231,  261 

Thoracic,  231,  261 
Intercosto-brachial,  231 
Intercosto-humeral,  231 
Intermedius   (glosso-palatine),   220, 

248,  310 
Interosseous.  Anterior  from  Median, 

229,  258 

from  Anterior  Tibial,  236 
Antibrachii  Dorsalis,  230 

Volaris,  229 
Posterior    from     Musculo-spiral, 

230,  258 

of  the  Intestines,  333,  336 
of  the  Iris,  28$ 
Ischiadicus,  234 
Jacobson's,  221,  250,  303 
of  the  Kidney,  363 
of  the  Knee-joint,  235 
Labial,  219,  246 
Lacrimal,  218,  246 
Lancisi's,  190 
Laryngeal,  External,  221,  250 

Inferior,  222,  250 

Internal,  221,  250 

Recurrent,  222,  250 

Superior,  221,  250 
of  the  Larynx,  354 
Lingual  from  Mandibular,  219,  246, 

from  Glosso-pharyngeal,  221,  250 
of  the  Liver,  340 
Lumbar,  232,  262 
Malar,  219,  220 
of  the  Mammary  Gland,  384 
Mandibular,  219,  246 
Masseteric,  219,  246 
Masticator,  201,  219,  246 
Mastoid,  227 
Maxillary,  218,  246 
Median,  229,  258 
of  Membrana  Tympani,  299 
Meningeal,  from  sth,  219,  246 

from  loth,  221,  250 

from  I2th,  222,  250 

of  the  Cord,  227 

Recurrent,  227 
Mental,  219 
Motor-oculi,  217,  244 
Musculo-cutaneous    of    Arm,    229, 
258 

of  leg,  236,  267 
Musculo-spiral,  230,  255 
Mylo-hyoid,  219,  246 
Nasal,  218,  219,  246 

Posterior  Inferior,  224 
Superior.  224 


Nerves,  Nasal,  Superior,  224 
Naso-ciliary,  218 
Naso-palatine,  224 
Ninth  Cranial,  221,  250 
of  the  Nose,  279 
Obturator,  232,  244,  264 

Accessory,  232,  264 
Occipital,  Great,  227,  254 

Small,  227,  254 
Occipitalis  Magnus,  227 

Minimus,  227 
Oculo-motor,  217,  244 
Oesophageal,  222,  250 
Olfactory,  216,  244 
Ophthalmic,  218,  246 
Optic,  217,  244,  291 
Orbital,  219,  224,  246 
of    Orientation     (vestibular) ,    221, 

252,  311 

of  the  Ovary,  383 
Palatine,  Anterior,  224 

External,  224 

Large,  224 

Medial,  224 

Middle,  224 

Posterior,  224 

Small,  224 

Palmar,  229,  230,  258,  260 
Palpebral,  219,  246 
of  the  Parotid,   219,  246 
Pars   Intermedia    (glosso-palatine), 

220,   248,  310 

Patheticus,  217 

Path,     Optic-acustic     Reflex,     199, 

200 

of  the  Penis,  372 
Peronaeus  Profundus,  236 

Superficials,  236 
Petrosal,  Deep,  237 

Great  Superficial,  225 

Small  Superficial,  225 
Pharyngeal,  224 

from  Ninth  Cranial,  221,  250 

from  Tenth  Cranial,  221,  250 
Phrenic,  228,  254 
Plantar,  235,  267 
Plexuses,  see  Plexus 
Pneumogastric,  221,  250 
Popliteal,  External,  235,  267 

Internal,  235,  267 
Portio  Dura,  220 

Mollis,  220 

of  the  Prostate  Gland,  371 
Pterygoid,  External,  219,  246 

Internal,  219.  246 
Pterygo-palatine,  224 
Pudenda!  Inferior,  234 

Long,  234 
Pudendus,  234 
Pudic,  234,  266 
Pulmonary,  222,  250 
Radial,  230,  256 
Radialis,  230,  256 
Rami   Communicantes,   Gray,  227, 

238 

White,  227.  238 
Respiratory,  of  Bell,  229 

External,  229 


422 


INDEX 


Nerves,  Respiratory,  Internal,  228 
Sacral,  233,  262 
Saphenous,  External,  235,  267 

Internal,  233,  264 

Long,  233, 264 

Short,  235,  266 
Sciatic,  Great,  234,  266 

Small,  234,  266 
Scrotal,  232 

Second  Cranial,  217,  244,  291 
Seventh  Cranial,  220,  248 
of  Shoulder-joint,  65 
Sixth  Cranial,  219,  252 
of  the  Spermatic  Cord,  377 
Spheno-palatine,  219,  246 
Spinal,  216,  226,  254 

Accessory,  222,  250 
Splanchnic,  Great,  227,  238,  268 

Small,  227 

of  the  Spleen,  241,  349 
of  the  Stomach,  330 
Stylo-hyoid,  220,  248 
Stylo-pharyngeal,  221,  250 
Suboccipital,  227,  254 
Subscapular,  229,  260 
Superficialis  Colli,  227,  254 
Supra-aero mial,  228 
Supra-clavicular,  228 
Supra-orbital,  218,  2^6 
of  the  Supra-renal  Gland,  365 
Suprascapular,  229 
Suprasternal,  228 
Supratrochlear,  218,  246 
Sural,  235,  236 
Sympathetic,  236,  268 
of  Taste,  275,  276 
Temporal,  Deep,  219,  246 

Superficial,  220,  248 

Superior,  219,  246 
Temporo-facial,  220,  248 
Temporo-malar,  219 
Tensoris  Tympani,  225 

Veli  Palatim,  225 
Tenth  Cranial,  221,  250 
Terminations  of,  177 
of  Testicle,  375 
Third  Cranial,  217,  244 
Thoracic,  231 

Anterior,  229,  258,  260 

Intercostals,  261 

Long,  229,  256 

Posterior,  229,  256 
Thoraco-dorsalis,  229 
of  Thymus  Gland,  347 
Thyro-hyoid,  222,  252 
of  Thyroid  Gland,  346 
Tibial,  Anterior,  236,  267 

Posterior,  235,  267 
Tibialis,  235 
of  the  Tongue,  275,  276 
Tonsillar,  221,  250,  315 
of  Trachea,  356 
Trifacial,  218,  246 
Trigeminal,  218,  246 
Trochlear,  217,  244 
Trancus  Lumbo-sacralis,  233 
Twelfth  Cranial,  222,  252 
Tympanic,  220,  248,  303 


Nerves  of  Tympanic  Membrane,  299 

of  Tympanum,  303 

Ulnar,  229,  256,  260 

of  the  Ureters,  364 

of  the  Uterus,  382 

of  the  Vagina,  380 

Vagus,  221,  250 

Vaso-motor,  122 

Vedian,  226 

of  the  Vesiculse  Seminales,  377 

of  the  Vulva,  379 

Wrisberg's,  229 

of  Wrist-joint,  230 

Zygomatic,  219 

Zygomatico-facial,  219 

Zygomatico-temporal,  219 
Nervous  System,  175,  242 

Tables  and  Plates,  242 
Neurilemma,  177 
Neuroglia,  176,  214 
Neurology,  i 
Neurones,  176 


Nipple,  384 
Nodule, 


207 

Noduli  Lymphatici  Agregati,  333 
Lienalis,  349 

Valvarum  Semilunarum,  120 
Nose,  276 

Vestibule  of,  176 
Notch,  Cerebellar,  206 

Cotyloid,  12 

Ethmoidal,  16 

Frontal,  15 

Great  Sciatic,  13 

Interclavicular,  8 

Intercondylar,  54 

Lesser  Sciatic,  13 

Nasal,  15 

Popliteal,  53 

of  Rivini,  298 

Sacro-iliac,  13 

Sacro-sciatic,  13 

Sigmoid,  34 

Supraorbital,  14,  37 

Suprascapular,  46 

Thyroid,  350 

Ulnar,  50 
Nuchal  Crest,  17 

Ligament,  61,  88 

Lines,  17 

Nuck's  Canal,  381 
Nucleus  or  Nuclei,  Abducent,  204 

Amygdalae,  179 

Anterior,  193 

Auditory,  204 

Caudatus,  191 

Cerebellar,  208 

Cuneatus,  198 

Dentate,  208 

Dorsal,  210,  216 

Emboliformis,  208 

Facial,  204 

Fastigii,  208 

Fourth  Ventricle,  212 

Globosus,  208 
'Gracilis,  198 

Habenulse,  194 

Hypo-thalamicus,  203 


INDEX 


423 


Nucleus,  Lenticular,  192 

Lentiformis,  192 

Lentis,  of  Crystalline  Lens,  288 

Mesencephalic  of  Masticator,  202 

Olivary,  Accessory,  209 
Inferior,  209 
Superior,  204 

Pontis,  204 

Red,  197 

Roof,  208 

Stilling's,  208 

Tegmenti  Ruber,  197 

Trigeminal,  204 
Nuhn's  Glands,  274 
Nymphae,  377 

OBEX,  212 
Occipital  Bone,  17 
Odontoblasts,  319 
Odontoid,  3 

Process,  7 
(Esophagus,  322 
Olive,  209 
Omenta,  326 
Omentum,  Gastro-colic,  326 

Gastro-hepatic,  326 

Gastro-splenic,  326 

Great,  326 

Lesser,  326 

Opening,  Saphenous,  108,  389 
Optic  Thalamus,  193 
Ora  Serrata,  285 
Orbiculus  Ciliaris,  283 
Orbit,  35 
Organ  or  Organa — 

Accessoria  Oculi,  293 

Auditus,  296 

of  Corti,  309 

of  Digestion,  312 

of  Equilibration,  309 

of  Generation,  Female,  377 
Male,  370 

of  Hearing,  296 

of  Jacobson,  278 

of  Orientation,  309 

of  Rosenmuller,  383 

of  Sight,  280 

of  Smell,  276 

of  Special  Sense,  270 

Spirale,  309 

of  Taste,  273 

of  Touch,  272 

Urinary,  360 

of  Voice  and  Respiration,  350 

Vomero-nasale,  278 
Orientation,  309 
Orificium  Uteri,  380 
Os  or  Ossa,  see  Bones 
Ossicula  Auditus,  301 
Ossification,  4 
Osteology,  i 
Ostium  Arteriosum,  121 
Pulmonis,  120 

Venosum  Ventriculi  Sinistri,  121 
Ptoconia,  307 
Otoliths,  307 
Ovaries,  382 


Ovicapsule,  383 
Oviducts,  382 

PACCHIONIAN  Bodies,  181,  182 
Paccinian  Corpuscles,  177,  272 
Palate,  313 

Bone,  31 

Pampiniform  Plexus,  375,  383 
Pancreas,  3*13 

Lesser,  344 
Panniculus  Adiposus,  74 

Carnosus,  74 
Papilla,  Lacrimal,  294 
Optic,  286 
Spiralis,  309 

Papillae  Circumvallate,  274 
Filiformes,  274 
of  Kidney,  361 
of  Mammae,  384 
of  Skin,  271 
of  Tongue,  274 
Vallatae,  274 
Paraganglia,  345 
Parathyroid  Glands,  346 
Parietal  Bone,  16 
Parotid  Gland,  315 
Parovarium,  383 
Pars  Ciliaris  Retinae,  285 

Flaccida  Membranae  Tympani,  298 
Intermedia,  220,  276 
Iridica  Retinae,  285 
Patella,    54 

Path,  Optic-acustic  Reflex,  199,  200 
Pecten  Ossis  Pubis,  14 
Pedicles,  5 

Peduncles  of  Cerebellum, Inferior,2O7, 209 
Middle,  204,  207 
Superior,  201,  207 
of  Cerebrum,  195 
Pelvis,  9 

Cavity  of,  391 
Fasciae  of,  391 
of  the  Kidney,  363 
Penis,  371 
Pericardium,  n8 
Pericementum,  319 
Perilymph,  304 
Perinaeal,  Body,  395 
Fossae,  393 
Interspaces,  393 
Perinaeum,  Proper,  391 
Female,  395 
Male,  392 
Perineurium,  177 
Periosteum,  4 
Peritoneum,  325 
Peroneal  Bone,  55 
Peroneus,  55 
Pes  Accessorius,  191 
Anserinus,  220 
Hippocampi,  191 
Petiolus  Epiglottidis,  352 
Petit's  Canal,  288,  289 
Petro-mastoid  Bone,  19 
Peyer's  Glands,  333 
Phaerochrome  System,  344 
Phalanges,  52,  58 
Pharyngeal  Cushion,  321 


424 


INDEX 


Pharynx,  320 

Pia  Mater,  182,  213 

Pillars  of  the  Fauces,  314 

of  the  Abdominal  Ring,  386 
Pjlli,  273 

Pineal  Gland,  194 
Pinna  of  the  Ear,  297 
Pituitary  Body,  186 
Plate,  Cribriform,  26 

Orbital  of  Ethmoid,  26 
of  Frontal,  15 

Perpendicular,  26 

Tarsal,  294 
Pleurae,  356 
Plexus,  Aortic,  2JT,  268 

Brachial,  228,  256 
Tabulated,  230 

Cardiac,  239 
'     Cartoid,  237,  268 

Cavernous,  237,  268 

of  the  Clitoris,  242 

Cervical,  227 

Choroid,  190 

Cceliac,  240 

Colic,  Left,  241 

Coronary,  239,  241 

Cystic,  241 

Diaphragmatic,  240 

Epigastric,  240 

Gastric,  Inferior,  241 
Superior,  241,  250 

Gastro-duodenal,  241 

Gastro-epiploic,  241 

Gullae  (oesqphageal) ,  323 

Haemorrhoidal,  Inferior,  242 
Superior,  241 

Hepatic,  241,  300 

Hypogastric,  241,  268 

Interlobular,  342 

Lienal,  241,  349 

Lumbalis,  232 

Lumbar,  232,  262 

Mesenteric,  Inferior,  241 
Superior,  241 

(Esophageal,  222,  250,  323 

Olfactory,  279 

Ovarian,  2^10,  241 

Palatine,  315 

Pampiniform,  375,  383, 

Pelvic,  2di,  268 

Pharyngeal,  237,  268,  315,  322 

Phrenic,  240 

Prostatic,  242 

Pudendal,  234 

Pulm9nary,  239,  268,  358 

Pyloric,  2A I 

Renal,  2^0,  263 

Sacral,  233,  262 

Sigmoid,  241 

Solar,  240 

Spermatic,  2di 

Spinosus,  219 

Splenic,  241,  349 

Supra-renal,  240 

Tympanic,  303 

Uterine,  2J2 

Vaginal,  242,  380 

Vesical,  242 


Plexuses  of  the  Sympathetic,  239,  268 
Plica  or  Plicae — 

Alares,  70 

Arytaeno-epiglotticae,  352 

Glosso-epiglotticae,  353 

Lacrimalis,  296 

Palmatse,  380 

Recto-uterinae,  381 

Semilunaris,  295,  314 

Syriovialis  Patellaris,  71 

Transyersales  Recti,  335 

Ventriculares,  353 

Vocales,  353 
Point,  Central  Tendinous  of  Perinaeum, 

394 

Pomum  Adami,  350 
Pons  Hepatis,  338 

Tarini,  188 

Varolii,  203 
Porta  Hepatis,  338 
Portal  System,  170 
Porus  Opticus,  286 
Pouch,  Douglas,  327 

Laryngeal,  354 

Peritoneal,  327 

Recto-vaginal,  327,  366 

Recto-vesical,  327,  366 

Utero-vesical,  327,  366 

Umbilical,  367 

Poupart's  Ligament,  108,  387 
Praeputium,  372 
Precuneus,  185 
Prepuce  of  the  clitoris,  377 

of  the  Penis,  372 
Process,  Acromion,  46 

Alveolar,  29 

Angular,  15 

Articular,  5 

Auditory,  25 

Basilar,  18 

Clinoid,  22,  24 

Condylar,  34 

Coracoid,  46 

Coronoid,  34,  49 

Ethmoidal,  22 

Falciform,  390 

Frontal,  28 

Fronto-sphenoidal,  30 

Hamular,  25,  29 

Jugular,  1 8 

Lacrimal,  32 

Malar,  28 

Mastoid,  20 

Maxillary,  32 

Mental  (mentum;  chin),  33 

Nasal,  28 

Odontoid,  7 

Olecranon,  48 

Olivary,  22 

Orbital,  30,  32 

Palatine,  29 

Pterygoid,  25 

Pyramidal,  32 

Sphenoidal,  32 

Spinous,  6 

Styloid,  21,  49,  50,  55 

Transverse,  5 

Turbinal,  26 


INDEX 


425 


Process,  Unciform,  26 

Uncinate,  26 

Vaginal,  21 

Vermiform,  206,  334 

Zygapophyseal,  5 

Zygomatic,  19,  28 
Processes,  Ciliary,  284 

Clinoid,  23 

of  Ingrassias,  24 
Processus,  Anterior,  301 

Cochleariformis,  21,  301 

Gracilis,  301 

Lateralis,  301 
Prominence,  Laryngeal,  350 

Tuhal,  321 
Promontory,  of  Cochlea,  300 

of  the  Facial  Canal,  300 

of  the  Sacrum,  n 

of  the  Tympanum,  300 
Prosencephalon,  178 
Prostate  Gland,  370 
Protuberance,  Occipital,  17,  1 8 
Psalterium,  190 
Pterygoid,  3,  25 
Pubes,  14 

Pudendum  Muliebre,  377 
Pulmones,  357 
Pulpa  Dentis,  318 

Lienis,  349 
Pulvinar,  193 
Punctum  Lacrimale,  294 
Pupil  or  Pupilla,  285 
Purkinje's  Cells,  176,  208 
Pylorus,  329 
Pyramid  of  the  Cerebellum,  207 

of  the  Medulla,  209 

Posterior,  210 

of  the  Thyroid  Gland,  345 

of  the  Tympanum,  301 
Pyramids  of  Ferrein,  362 

of  Malpighi,  362 

of  Wistar  (sphenoidal  turbinals),  24 

QUADRATE  Lobe,  338 

Lobule  (cuneus),  186 
Quadratus  Femoris,  112 

Labii,  78 

Lumborum,  97 

Menti,  78 

Suadriceps  Femoris,  108 
uadrigeminal  Bodies,  202 

RADIUS,  49 

Rami,  Communicantes,  227,  238 

Ramus,  Ischio-pubic,  12 

mandibular,  34 
Raph6  of  Medulla,  211 

of  the  Perinaeum,  392 

of  the  Tongue,  274 
Receptaculum  Chyli,  172 
Recess  or  Recessus — 

Atic,  300 

Cochlearis,  305 

Duodeno-jejunalis,  328 

Ellipticus,  305 

Epitympanic,  300 

Ileo-caecalis,  328 

Incudis,  300 


Recess,  Naso-palatine,  278 

Sphaericus,  305 

Spheno-ethmoidal,  277 
Rectum,  335 
Region  or  Regions,  Abdominal,  95,  323 

of  the  Arm,  100 

Buccal,  78 

Cervical,  80,  84 

Cranial,  75 

Dorsal,  86 

of  the  Ear,  86 

Epigastric,  324 

of  the  Forearm,  102 

Gastric,  324 

Gluteal,  no 

of  the  Hand,  105 

Hyoid,  8 1 

Hypo-chondriac,  324 

Hypo-gastric,  324 

Hypo-thalamic,  202 

Iliac,  324 

Inguinal,  324,  385 

Ischio-rectal,  97 

Laryngeal,  86,  88 

Lingual,  82 

Lumbar,  324 

Mandibular,  78 

Maxillary,  77 

Nasal,  77 

Orbital,  76 

Palatal,  183 

Palmar,  105 

Palpebral,  75 

Pelvic,  97 

Perineal,  98,  99 

Pharyngeal,  83 

Plantar,  116 

Pre vertebral,  84 

Pterygoid,  79 

of  Shoulder,  100 

Suboccipital,  88,  93 

Temporo-mandibular,  79 

Thoracic,  93,  99 

of  Thigh,  112 

Tympanic.  80 

Umbilical,  324 

Vertebral,  84,  85 
Reil,  Island  of,  183 
Renes,  360 
R6te.  Carpi,  135 

Mucosum,  270 

Testis,  374 

Rcticular  Formation,  211 
Retina,  285,  286 
Rhombencephalon,  203 
Ribes,  Ganglion  of,  236,  268 
Ribs  (costae),  8 
Ridge,  of  Aquseductus  Fallopii,  300 

Articular  of  Temporal.  19 

Condylar  of  Humerus,  48 

Crucial,  18 

Gluteal,  13 

Infra-temporal,  24 

Inter-trocnanteric,  53 

Mylo-hyoid,  34 

Nuchal,  17 

Pterygoid,  24 

Suprameatal,  19 


426 


INDEX 


Ridge,  Temporal,  16 
Rima  Glottidis,  353 

Palpebrarum,  293 
Ring,  Abdominal,  Deep,  385 
External,  386 
Internal,  385 
Superficial,  386 

Crural,  389 

Femoral,  389 

Inguinalis  Abdominalis,  385 

Subcutaneous,  386 
Rivinius,  Duct  of,  316 

Notch  of,  298 
Rods  and  Cones,  287 

of  Corti,  310 
Rolando,  Fasciculus  of,  209 

Fissure  of,  184 
Root,  Descending  or  Mesencephalic  of 

the  Trigeminal  Nerve,  201 
Rosenmiiller's  Fossa,  322 

Gland,  295 

Organ,  383 
Rostrum,  3 

of  the  Sphenoid,  24 
Rugae  Vaginales,  379 

SAC  of  Hilton,  354 

Lacrimal,  296 

Peritoneal,  325 
Saccule,  304 
Sacculus  Laryngis,  354 
Sacro-sciatic  Foramen,  64 

N9tch,  13 
Santorini's  Cartilages,  352 

Muscle  (risorius),  79 
Saphenous  Opening,  108,  389 
Sapolini,  on  the  Chorda  Tympani,  276 
Scala  Media,  309 

Tympani,  307 

Vestibuli,  307 
Scapha  Auriculae,  297 
Scaphoid  Bone,  51,  57 
Scapula,  45 
Scarf-skin,  270 
Scarpa's  Fascia,  108,  385 

Foramen,  29 

Ganglion,  311 

Triangle,  142 
Schachowa's  Tubes,  362 
Schreger's  Lines,  319 
Schindylesis,  59 
Schlemm's  Canal,  282 
Schultze's  Olfactory  Cells,  278 
Schwann,  Substance  of,  177 
Sclerotic,  281 
Scrotum,  373 
Sella  Turcica,  22 
Sense,  Special,  270 
Septum  Canalis  Musculo-tubarii,  301 

Crurale,  389 

Femorale,  389 

Lucidum,  190 

Narium,  276 

Nasi,  276 

Pectiniforme,  371 

Pellucidum,  190 

Transversum,  309 

Tubae,  21 


Sheath,  Crural,  390 

Femoral,  390 
Shin-bone,  54 
Shoulder,  44,  65 
Shoulder-blade,  45 
Shrapnell's  Membrane,  298 
Sight,  Organ  of,  280 
Sigmoid  Flexure,  334 
Sinus,  Coronary,  171 

Maxillaris,  27 

of  Morgagni,  354 

Pocularis,  368 

Prostatic,  368 

Renis,  361 

Tonsillaris,  314 

Venosus,  119,  282 
Sinuses,  of  the  Dura  Mater,  164 

Frontal,  15 

Meningeal,  164 

Sphenoidal,  23 

of  Valsalva,  120 

Venous,  163 
Skin,  270 

Appendages  of,  272 
Skull,  Base  of,  41 

Fossse  of,  41,  42 

Slit,  Nasal  (ethmoidal  fissure),  38,  41 
Smell,  Organ  of,  276 
Socia  Parotid  is,  316 
Space,  Haversian,  4 

Inter-peduncular,  189 

Ischio-rectal,  394 

Perforated,  186,  188,  193 

Perinaeal,  393 

Popliteal,  54 

Subarachnoid,  181 

Subdural,  181 
Spaces  of  the  Eyeball,  290 

Fontana's,  282 
Spatia  Anguli  Iridis,  282 

Zonularia,  288,  289 
Spermatic  Cord,  376 
Sphenoid  Bone,  22 
Sphincter  Pupillae,  285 

Vaginae,  99 

Vesicae,  367 
Spinal  Cord,  213 
Spine,  Alar,  24 

Ethmoidal,  22 

Frontal,  15 

of  the  Ilium,  13 

of  the  Ischium,  13 

Mandibular,  34 

Nasal,  15,  29,  31 

Pharyngeal,  18 

of  the  Pubis,  14 

of  the  Scapula,  45 

of  the  Sphenoid,  22 

of  Spix  (mandibular),  34 

of  the  Tibia,  54 
Spinous,  3 
Splanchnology,  i 
Spleen,  348 
Spot,  Blind,  286 

Yellow,  285 
Squamous,  3 

Bone,  19 
Stapes,  301 


INDEX 


427 


Stenson's  Duct,  316 

Foramen,  29 
Sternum,  8 
Selling's  Canal,  288 

Roof  Nucleus,  208 
Stomach,  328 
Stratum  Cinereum,  202 

Corneum,  270 

Germinativum,  270 

Granulosum,  270 

Griseum  Centrale,  197 
Colliculi  Superioris,  202 

Intermedium,  197 

Lemnici,  202 

Lucidum,  270 

Malpighii,  270 

Opticum,  202,  286 

Zonale,  202 
Stria  Terminalis,  190 
Striae  Acusticae,  212 

Longitudinales,  190 

Medullares,  212 

Obliquae,  212 
Stripe,  Malleolar,  298 
Styloid,  3 

Process,  21 
Submaxillary,  now  called  Submandibu- 

lar— 
Substantia  Adamantina,  319 

Alba,  see  White  Matter,  177 

Eburnea,  319 

Gelatinosa  (Rolandi),  204,  209 

Grisea,  see  Gray  Matter,  176 

Ossea,  319 

Perforata,  186,  188,  193 
Sulci,  183,  see  also  Grooves  and  Fissures 
Sulcus  Cerebri  Centralis,  184 

Chiasmatis,  22 

Longitudinalis  Medianus,  212 

Medianus  Linguae,  274 

Nervi  Oculo-motorii,  22 
Radialis,  47 

Sagittalis,  15 

Spiralis  Internus,  309 

Tympanicus,  298 
Supercilia,  293 
Sustentaculum  Tali,  57 
Sutura,  59 
Suture  or  Sutures — 

Coronal,  16,  40 

Cranial,  40 

Facial,  40 

Lambdoid,  16 

Metppic,  14 

Orbital,  37 

Sagittal,  16,  40 
Sylvius,  Aquaeduct  of,  202 

Fissure  of,  184 

Sympathetic  System,  236,  268 
Symphysis,  33,  59,  64 
Synarthrosis,  59 
Synovia,  60 

Synovial  Membranes,  60 
Syndesmology,  i,  58 
Syndesmosis,  59 
System,  Arterial,  122 

Cerebro-spinal  Nervous,  178 

Chromaffin,  344 


System,  Chromaphil,  344 
Haversian,  4 
Lymphatic,  171 
Nervous,  175 
Phaerochrome,  344 
Portal,  170 

Sympathetic  Nervous,  236,  268 
Vascular,  118 
Venous,  163 

TAPETUM,  283,  286 

Tarsi,  294 

Tarsus,  57 

Taste,  Nerves  of,  275 

Taste-buds,  275 

Taenia  Hippocampi,  190 

Semicircularis,  190 
Tectum,  202 

Mesencephali,  202 
Teeth,  31? 

Development  of,  319 

Eruption  of,  320 
Tegmentum,  197 
Tela  Choroidea  Inferior,  211 
Ventriculi  Tertii,  190 

Subcutaneous,  74 
Telencephalon,  178 
Temporal  Bone,  19 
Tendo  Oculi,  294 
Tendon  of  Achilles,  113 

Conjoined,  95 
Tendons,  74 
Tenon's  Capsule,  280 
Tentqrium  Cerebelli,  181 
Terminal  Organs,  177 
Testes,  392 

Appendages  of,  375 

Coverings  of,  373 

Descent  of,  375 

Quadrigeminal,  202 
Testicle,  392 
Thalamencephalon,  192 
Thalamus  Opticus,  193 
Thebesius,  Foramena  of,  119 
Thenar  Eminence,  106 
Thigh,  112 
Thorax,  7,  93,  99 
Thymus  Gland,  347 
Thyro-hyal,  41 
Thyroid  (or  thyreoid)  Axis,  131,  152 

Cartilage,  350 

Gland,  345 
Tibia,  54 
Tissue,  Erectile,  371 

Gray  Nervous,  176 

White  Nervous,  177 
Todd  and  Bowman,  Muscle  of,  309 
Tongue,  273 

Muscles  of,  82,  83 
Tonsil,  Cerebcllar,  207 

Palatine,  314 

Pharyngeal,  321 
.     Tubal,  303 

Torcular  Herophili,  18,  165 
Torus  Tubarius,  321 
Trabeculse  Lienis,  349 
Trachea,  355 
Tract,  see  also  Fasciculus 


428 


INDEX 


Tract,    Anterior    (or  direct)  Pyramidal, 

196,  214 
Ascending  Antero-lateral  (Gower's), 

205,  214 

Caudate-cerebellar,  197 
Central  Tegmental,  202 
Cerebro-spinal,  196,  214 
Cortico-pontine,  19? 
Crossed  Pyramidal,  196,  214 
Descending    Root    of    Trigeminus, 

201 
Direct  Cerebellar  (Flechsig's),  210, 

215 
Direct  (or  anterior)  Pyramidal,  196, 

214 

Flechsig's,  210,  215 
Fronto-pontine,  197 
Gower's,  205,  214 
Indirect  Motor,  197 
Lissauer's,  215 
Mesencephalic  Root  of  Trigeminus, 

2OI 

Mesencephalo-    (or  tecto-)    Spinal, 
199 

Monakow's,  201 

Motor,  Direct,  196 
Indirect,  197 

Postero-lateral,  215 

Pre-pyramidal,  201 

Pyramidal,  196 

Rolando's,  209 

Rubro-spinal,  201 

Solitary,  211.  221 

Spino-cerebellar,  205,  214 

Spino-thalamic,  200 

Tecto-   (or  mesencephalo-)    Spinal, 
199 

Temporo-pontme,  197 

Thalamo-olivary,  202 

Transverse  Peduncular,  180 

Uncrossed  Pyramidal,  196 

Uveal,  281 

Ventral  Spino-cerebellar,  205,  206 

Ventro-lateral  Spino-cerebellar,  205, 

206 

Tractus  Spiralis  Foraminosus,  311 
Tragus,  297 

Trapezium  Medullas  Oblpngatae,  204 
Triangle,  Anterior,  Cervical,  128 

Carotid,  129 

Femoral,  142 

Habenular,  194 

Hesselbach's,  387 

Interosseous  of  Fibula,  56 

Occipital,  130 

Posterior  Cervical,  130 

Scarpa's,  142 

Subclavian,  130 

Subcutaneous  of  Fibula,  56 

Submandibular,  129 

Submaxillary,  129 
Triangles  of  the  Neck,  128 
Trigonum  Acustici,  212 

Collaterale,  191 

Femorale,  142 

Habenulae,  194 

Hypoglossi,  212 

Olfactorium,  217 


Trigonum  Vagi,  212 

Vesicse,  367 

Triquetrum  (cuneiform),  51 
Trochanters,  3 

of  Femur,  53 
Trochlea,  of  Humerus,  48 

of  the  Orbit,  289 
Trochlear,  3 

Nerve,  217,  244 
Trochoides,  59 
Tuba  Auditiva,  303 
Tuba?  Uterinae,  382 
Tube  or  Tubes — 

Eustachian,  303 

Fallopian,  382 

Neural,  178 

of  Shachowa,  362 
Tube-tonsil,  303 
Tuber  Cinereum,  186 

Valvulas,  207 
Tubercle  or  Tubercles,  3 

Adductor,  54 

Amygdaloid,  179 

Anterior  of  the  Thalamus,  193 

Bicipital,  49 

Darwin's,  297 

Genial,  34 

of  Humerus,  47 

of  Lower,  120 

Pharyngeal,  18 

Zygomatic,  19 
Tuberculum,  Acusticum,  212 

Auriculae,  297 

Intervenosum,  120 

Sellse,  22 
Tube^sity  or  Tuberosities,  3 

Bicipital,  49 

of  Femur,  54 

of  Humerus,  47 

of  Ischium,  14 

Malar,  30 

Maxillary,  28 

of  Palate,  32 

of  Radius,  49 

of  Tibia,  54 

of  Ulna,  49 
Tubules  or  Tubuli— 

Convoluted,  362 

Dentinal,  319 

Lactiferi,  384 

Renales,  362 

Seminiferi,  374 

Spiral,  362 

Uriniferi,  362 
Tuft,  Malpighian,  361 
Tunica  Albugenia,  374 

Conjunctiva,  294 

Fibrosa  Oculi,  281 

Interna  Oculi,  285 

Ruyschiana,  283 

Vaginalis  Testis,  374 

Vascu^sa  Oculi,  283 

Testis,  374 
Tunics  of  the  Eyeball,  281 

of  the  Testicle,  374 
Turbinals,  32 

Sphenoidal,  24 
Tutamina  Oculi,  293 


INDEX 


429 


Tympanic  Bone,  21 
Tympanum,  300 
Tyson's  Glands,  372 

ULNA,  48 

Umbilical  Region,  324 
Umbilicus,  324 
Umbo,  298 
Unciform,  3 
Uncinate  Gyrus,  186 
Ungues.  272 
Urachus,  366 
Ureters,  363 
Urethra,  Female,  370 

Male,  368 

Urogenital  Diaphragm,  393 
Uterus,  380 

Appendages  of,  382 

Masculinus,  368 
Utricle,  307 

Utriculus  Prostaticus,  368 
Uvea,  285 
Uveal  Tract,  281 
Uvula,  313 

Cerebelli,  207 

Vesicae,  367 

VAGINA,  379 
Vaginal,  3 

Process,  21 
Vallecula,  206 

Valsalva,  Sinuses  of,  120,  122 
Valve  of  Bauhin,  331,  334 

Coronary,  120 

Eustachian,  120 

of  Hasner,  296 

Ileo-caecal,  331,  334 

Mitral,  121 

Pyloric,  329 

of  Thebesius,  120 

Tricuspid,  120 

of  Vieussens,  203,  207 
Valves,  Aortic  Semilunar,  121 

of  Houston,  335 

of  Kirkring,  332 

Pulmonary,  120 

Semilunar,  120,  122 
Valvulae  Coli,  334 

Conniventes,  332 

Sinus  Coronarii,  120 

Venae  Cavae  Inferioris,  120 
Vas  Aberrans,  373 

Deferens,  375 

Spirale,  309 
Vasa  Efferentia,  374 

Recta,  374 

Vasorum,  122 
Vein  or  Veins,  163 

Angular,  164 

Auricular,  164 

Axillary,  166 

Azygps,  167 

Basilic.  166 

Bronchial,  356 

Cardiac,  171 

Cephalic,  166 

Cerebellar,  164 

Cerebral,  164 


Veins,  Choroid,  283 
Cystic,  170 
Emissary,  165 
Facial,  164 
Femoral,  168 
Frontal,  163 
Gastric,  170 
Hepatic,  170,  3  2 
Iliac,  169 
Innominate,  166 
Intercostal,  167 
Interlobular,  342 
Intralobular,  342 

£ugular,  165 
ienal  (splenic),  170 
Lobular,  342 
Lumbar,  170 
Mammary,  167 
Maxillary,  164 
Median,  166 
Mesenteric,  170 
Occipital,  164 
Ovarian,  170 
Phrenic,  170 
Popliteal,  1 68 
Portal,  170,  341 
Pulmonary,  163 
Radial,  166 
Renal,  170,  363 
Saphenous.  168,  169 
Spermatic,  170 
Spinal,  168 
Splenic,  170.  349 
Subclavian,  166 
Sublobular,  342 
Supraorbital,  163 
Supra-renal,  170 
Temporal,  164 
Thyroid,  167 
Ulnar,  166 
Uterine,  382 
Vertebral,  166 
Veins  of  the  Abdomen,  169 
Bladder,  368 
Bone,  4 
Diploe,  164 
Ear,  312 

Head  and  Neck,  163 
Heart,  171 
Intestine,  333,  336 
Kidney,  363 
Larynx,  354 
Liver,  341,  342 
Lower  Extremity,  168 
Lung,  359 

Mammary  Gland,  384 
Membrana  Tympani,  299 
Neck,  165 
Nose,  279 
(Esophagus,  323 
Ovaries,  383 
Pancreas,  344 
Pelvis,  169 
Penis,  372 
of  Pharynx,  322 
Prostate  Gland,  37 
Rectum,  336 
Stomach,  330 


43C 


INDEX 


Veins,  Supra-renal  Glands,  365 

Testicle,  375 

Thorax,  167 

Thymus  Gland,  347 

Thyroid  Gland,  346 

Tongue,  275 

Tonsil,  314 

Trachea  and  Bronchi,  356 

Tympanic  Membrane,  299 

Tympanum,  302 

Upper  Extremity,  166 

Uterus,  382 

Vagina,  379 

Without  Valves,  163 
Velum,  Inferior  Medullary,  212 

Interpositum,  190 

Superior  Medullary,  203,  207 
Vena  Cava,  Inferior,  170 

Superior,  168 
Venae  Comites,  163 

Galense,  185 

Proprise  Renales,  363 

Rectae,  363 

Vorticosae,  290 
Venous  Sinuses,  163 

System,  163 
Portal,  170 
Pulmonary,  163 
Systemic,  163 
Ventricle  of  Cerebellum,  211 

Lateral,  189 

Fifth,  191 

Fourth,  211 

Laryngeal,  354 

Nasal,  277 

Third,  189,  192 
Ventriculus,  328 
Vermis  Cerebelli,  206 

Superior,  207 
Vertebrae,  5 

Important  Relations  of,  7 
Vertebral  Aponeurosis,  90 
Verumontanum,  368 
Vesica  Fellea,  3^3 

Urinaria,  365 
Vesicle,  Graafian,  383 


Vesicles  of  the  Brain,  178 

Seminal,  376 
Vestibule  of  the  Ear,  305 

of  the  Larynx,  353 

of  the  Mouth,  312 

of  the  Nose,  277 

of  the  Vulva,  378 
Vidian  Canal,  25 
Vieussens,  Valve  of,  203,  207 
Villi  of  the  Intestine,  332 
Vinculum  Lingua?,  207 
Viscera  covered  by  Peritoneum,  327 
Vocal  Cords,  353 
Vomer,  33 

Vortex  of  the  Heart,  118 
Vulva,  377 

WAGNER'S  Corpuscles,  177 

Wharton's  Duct,  316 

White  Matter  of  the  Brain,  179 

Rami  Communicantes,  227 
Willis,  Circle  of,  128,  151 
Winslow's  Foramen,  326 

Ligament,  70 
Wirsung's  Duct,  344 
Worm,  207 

Wormian  Bones,  3,  40 
Wrisberg's  Cartilage,  352 

Ganglion,  239 

Ligament,  71 

Nerve,  229 

XYPHOID  Appendix,  8 
YELLOW  Spot,  285 

ZINN,  Ligament  of,  76 

Zonule,  288 
Zona  Arcuata,  309 

Pectinate,  309 
Zonula  Ciliaris,  288 
Zonule  of  Zinn,  288 
Zygapophyses,  5 
Zygoma,  19 
Zygomatic  Bone,  30 


2A>V0J^ cp&. 

(T 


;WU 

,) 

/   o<W 


HACKH-CHEMICAL  DICTIONARY 

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This  is  a  revision  of  the  second  edition  of  Lewis  and  Stohr's  Textbook  of  Histology, 
based  on  the  15th  Edition  of  Stohr's  Histology. 

HAWK     and     BERGEIM— PRACTICAL     PHYSIOLOGICAL     CHEMISTRY, 
9th  EDITION 

8  Full  Page  Colored  Plates,  273  Text  Illustrations,  Cloth,  $6.50 
By  Philip  B.  Hawk,  M.S.,  Ph.D.,  President,  Food  Research  Laboratories.  Inc. , 
New  York,  and  Olaf  Bergeim,  University  of  Illinois  College  of  Medicine. 
Urine  analysis,  blood,  sputum,  feces,  milk,  analyses,  etc.     A  study  of  enzymes 
in  the  body,  carbohydrates,  proteins,  gastric  digestion  and  analysis,  fats;  pan- 
creatic, intestinal    digestion;    bile,    putrefaction    products,    acidosis,  etc.,    etc. 
Complete,   Practical,   Comprehensible. 

UNDERBILL— TOXICOLOGY,  2d  EDITION 

By  Frank  P.  Underbill.  Ph.D.,  Professor  of  Pharmacology  and  Toxicology,  Yale 
University.  Cloth,  $2.50. 

BRUBAKER— A  TEXT-BOOK  OF  HUMAN  PHYSIOLOGY.  8th  EDITION 

By  Albert  P.  Brubaker,  A.M.,  M.D.,  Professor  of  Physiology  and  Hygiene. 
Jefferson  Medical  College.  Colored  Plate  and  367  Illustrations.  Cloth,  $5.00. 


